XENOPORT, INC. WARRANT TO PURCHASE [____] SHARES OF COMMON STOCK

Exhibit 4.1

XENOPORT, INC.

WARRANT TO PURCHASE [____] SHARES OF COMMON STOCK

Date of Issuance: [______] [__], 200__

VOID AFTER [______] [__], 200__

     This Certifies That, for value received, [___], or permitted registered assigns (the “Holder”), is entitled to subscribe for and purchase at the Exercise Price (defined below) from XenoPort, Inc., a Delaware corporation (the “Company”), up to [___] shares of the common stock of the Company, par value $.001 per share (the “Common Stock”). This warrant is one of a series of warrants issued by the Company as of the date hereof (individually a “Warrant”; collectively, “Company Warrants”) pursuant to those certain purchase agreements between the Company and each of the Investors, each dated as of December 30, 2008 (each, a “Purchase Agreement”).

     1. Definitions. Capitalized terms used herein but not otherwise defined herein shall have their respective meanings as set forth in the Purchase Agreement. As used herein, the following terms shall have the following respective meanings:

          (A) “Eligible Market” means any of the New York Stock Exchange, the American Stock Exchange, The NASDAQ Global Market, The NASDAQ Global Select Market or The NASDAQ Capital Market.

          (B) “Exercise Period” shall mean the period ending five years from the date hereof, unless sooner terminated as provided below.

          (C) “Exercise Price” shall mean $25.40 per share, subject to adjustment pursuant to Section 4 below.

          (D) “Exercise Shares” shall mean the shares of Common Stock issuable upon exercise of this Warrant.

          (E) “Fundamental Transaction” means that the Company shall, directly or indirectly, in one or more related transactions, (i) consolidate or merge with or into (whether or not the Company is the surviving corporation) another Person, or (ii) sell, assign, transfer, convey or otherwise dispose of all or substantially all of the properties or assets of the Company to another Person, or (iii) enter into an agreement with another Person pursuant to which such Person agrees to make a purchase, tender or exchange offer that is accepted by the holders of more than the 50% of the outstanding shares of Common Stock (not including any shares of Common Stock held by the Person or Persons making or party to, or associated or affiliated with the Persons making or party to, such purchase, tender or exchange offer), or (iv) consummate a stock purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with another Person

whereby such other Person acquires more than the 50% of the outstanding shares of Common Stock (not including any shares of Common Stock held by the other Person or other Persons making or party to, or associated or affiliated with the other Persons making or party to, such stock purchase agreement or other business combination), (v) reorganize, recapitalize or reclassify its Common Stock, or (vi) any “person” or “group” (as these terms are used for purposes of Sections 13(d) and 14(d) of the Exchange Act) is or shall become the “beneficial owner” (as defined in Rule 13d-3 under the Exchange Act), directly or indirectly, of 50% of the aggregate ordinary voting power represented by issued and outstanding Common Stock.

          (F) “Parent Entity” of a Person means an entity that, directly or indirectly, controls the applicable Person and whose common stock or equivalent equity security is quoted or listed on The New York Stock Exchange, Inc. or an Eligible Market, or, if there is more than one such Person or Parent Entity, the Person or Parent Entity with the largest public market capitalization as of the date of consummation of the Fundamental Transaction.

          (G) “Person” means an individual, a limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization, any other entity and a government or any department or agency thereof.

          (H) “Successor Entity” means the Person (or, if so elected by the Holder, the Parent Entity) formed by, resulting from or surviving any Fundamental Transaction or the Person (or, if so elected by the Holder, the Parent Entity) with which such Fundamental Transaction shall have been entered into.

          (I) “Trading Day” shall mean (a) any day on which the Common Stock is listed or quoted and traded on its primary Trading Market, (b) if the Common Stock is not then listed or quoted and traded on any Eligible Market, then a day on which trading occurs on the OTC Bulletin Board (or any successor thereto), or (c) if trading does not occur on the OTC Bulletin Board (or any successor thereto), any Business Day.

          (J) “Trading Market” shall mean the OTC Bulletin Board or any other Eligible Market, or any national securities exchange, market or trading or quotation facility on which the Common Stock is then listed or quoted.

     2. Exercise of Warrant.

          2.1 Exercise. The rights represented by this Warrant may be exercised in whole or in part at any time during the Exercise Period, by delivery of the following to the Company at its address set forth on the signature page hereto (or at such other address as it may designate by notice in writing to the Holder):

          (A) An executed Notice of Exercise in the form attached hereto;

          (B) Payment of the Exercise Price either (i) in cash or by check or (ii) pursuant to Section 2.2 below; and

          (C) This Warrant.

          Execution and delivery of the Notice of Exercise shall have the same effect as cancellation of the original Warrant and issuance of a new Warrant evidencing the right to purchase the remaining number of Exercise Shares, if any.

     Certificates for shares purchased hereunder shall be transmitted by the transfer agent of the Company to the Holder by crediting the account of the Holder’s prime broker with the Depository Trust Company through its Deposit Withdrawal Agent Commission system if the Company is a participant in such system, and otherwise by physical delivery to the address specified by the Holder in the Notice of Exercise within three business days from the delivery to the Company of the Notice of Exercise, surrender of this Warrant and payment of the aggregate Exercise Price as set forth above. This Warrant shall be deemed to have been exercised on the date the Exercise Price is received by the Company.

     The person in whose name any certificate or certificates for Exercise Shares are to be issued upon exercise of this Warrant shall be deemed to have become the holder of record of such shares on the date on which this Warrant was surrendered and payment of the Exercise Price was made, irrespective of the date of delivery of such certificate or certificates, except that, if the date of such surrender and payment is a date when the stock transfer books of the Company are closed, such person shall be deemed to have become the holder of such shares at the close of business on the next succeeding date on which the stock transfer books are open.

     Subject to the final sentence of this paragraph and to the extent permitted by law, the Company’s obligations to issue and deliver Exercise Shares in accordance with the terms hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any person or entity or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other person or entity of any obligation to the Company or any violation or alleged violation of law by the Holder or any other person or entity, and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Exercise Shares. The Holder shall, subject to the following proviso, have the right to pursue any remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver Exercise Shares upon exercise of this Warrant as required pursuant to the terms hereof; provided, however, that notwithstanding anything to the contrary in this Warrant or in the Purchase Agreements, if the Company is for any reason unable to deliver Exercise Shares upon exercise of this Warrant as required pursuant to the terms hereof, the Company shall have no obligation to pay to the Holder any cash or other consideration or otherwise “net cash settle” this Warrant.

     Except for cash in lieu of fractional shares as provided in Section 5, this Warrant may not be settled by the Company for cash to the Holder in lieu of Common Stock.

          2.2 Net Exercise. If during the Exercise Period the fair market value of one share of the Common Stock is greater than the Exercise Price (at the date of calculation as set forth below), in lieu of exercising this Warrant by payment of cash or by check, the Holder may, at its election, effect a “net exercise” of this Warrant, in which event, if so effected, the Holder

shall receive Exercise Shares equal to the value (as determined below) of this Warrant (or the portion thereof being canceled) by surrender of this Warrant at the principal office of the Company, together with the properly endorsed Notice of Exercise, in which event the Company shall issue to the Holder a number of shares of Common Stock computed using the following formula:

Where X = the number of Exercise Shares to be issued to the Holder

		Y = the number of Exercise Shares with respect to which this Warrant is being exercised
		A = the Fair Market Value (as defined below) of one share of the Company’s Common Stock (at the date of such calculation)
		B = Exercise Price (as adjusted to the date of such calculation)

     For purposes of this Warrant, the “Fair Market Value” of one share of Common Stock shall mean (i) the average of the closing sales prices for the shares of Common Stock on The NASDAQ Global Market or other Eligible Market where the Common Stock is listed or traded as reported by Bloomberg Financial Markets (or a comparable reporting service of national reputation selected by the Company and reasonably acceptable to the Holder if Bloomberg Financial Markets is not then reporting sales prices of such security) (collectively, “Bloomberg”) for the ten (10) consecutive trading days immediately prior to the Exercise Date, or (ii) if an Eligible Market is not the principal Trading Market for the shares of Common Stock, the average of the reported sales prices reported by Bloomberg on the principal Trading Market for the Common Stock during the same period, or, if there is no sales price for such period, the last sales price reported by Bloomberg for such period, or (iii) if neither of the foregoing applies, the last sales price of such security in the over-the-counter market on the pink sheets or bulletin board for such security as reported by Bloomberg, or if no sales price is so reported for such security, the last bid price of such security as reported by Bloomberg or (iv) if fair market value cannot be calculated as of such date on any of the foregoing bases, the fair market value shall be as determined by the Board of Directors of the Company in the exercise of its good faith judgment.

          2.3 Issuance Of New Warrants. Upon any partial exercise of this Warrant, the Company, at its expense, will forthwith and, in any event within five business days, issue and deliver to the Holder a new warrant or warrants of like tenor, registered in the name of the Holder, exercisable, in the aggregate, for the balance of the number of shares of Common Stock remaining available for purchase under this Warrant.

          2.4 Payment Of Taxes And Expenses. The Company shall pay any recording, filing, stamp or similar tax which may be payable in respect of any transfer involved in the issuance of, and the preparation and delivery of certificates (if applicable) representing, (i) any Exercise Shares purchased upon exercise of this Warrant and/or (ii) new or replacement warrants in the Holder’s name or the name of any transferee of all or any portion of this Warrant; provided, however, that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved in the issuance, delivery or registration of any certificates for

Exercise Shares or Warrants in a name other than that of the Holder. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Exercise Shares upon exercise hereof.

     3. Covenants of the Company.

          3.1 Covenants as to Exercise Shares. The Company covenants and agrees that all Exercise Shares that may be issued upon the exercise of the rights represented by this Warrant will, upon issuance, be validly issued and outstanding, fully paid and nonassessable, and free from all taxes, liens and charges with respect to the issuance thereof. The Company further covenants and agrees that the Company will at all times during the Exercise Period, have authorized and reserved, free from preemptive rights, a sufficient number of shares of Common Stock to provide for the exercise of the rights represented by this Warrant. If at any time during the Exercise Period the number of authorized but unissued shares of Common Stock shall not be sufficient to permit exercise of this Warrant, the Company will use its commercially reasonable efforts to take such corporate action in compliance with applicable law as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of Common Stock to such number of shares as shall be sufficient for such purposes.

          3.2 Notices of Record Date and Certain Other Events. In the event of any taking by the Company of a record of the holders of any class of securities for the purpose of determining the holders thereof who are entitled to receive any dividend or other distribution, the Company shall mail to the Holder, at least fifteen (15) days prior to the date on which any such record is to be taken for the purpose of such dividend or distribution, a notice specifying such date. In the event of any voluntary dissolution, liquidation or winding up of the Company, the Company shall mail to the Holder, at least fifteen (15) days prior to the date of the occurrence of any such event, a notice specifying such date. In the event the Company authorizes or approves, enters into any agreement contemplating, or solicits stockholder approval for any Fundamental Transaction, as defined in Section 6 herein, the Company shall mail to the Holder, at least fifteen (15) days prior to the date of the closing of such event, a notice specifying such date. Notwithstanding the foregoing, the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice.

     4. Adjustment of Exercise Price and Shares.

     The Exercise Price and number of Exercise Shares issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 4.

          (A) If the Company, at any time while this Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock that is payable in shares of Common Stock, (ii) subdivides outstanding shares of Common Stock into a larger number of shares, or (iii) combines outstanding shares of Common Stock into a smaller number of shares, then in each such case the Exercise Price shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event. Any adjustment made pursuant to clause (i) of this paragraph shall become effective immediately after the record date for the

determination of stockholders entitled to receive such dividend or distribution, and any adjustment pursuant to clause (ii) or (iii) of this paragraph shall become effective immediately after the effective date of such subdivision or combination.

          (B) If the Company, at any time while this Warrant is outstanding, distributes to holders of Common Stock (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case, “Distributed Property”), then in each such case the Holder shall be entitled upon exercise of this Warrant for the purchase of any or all of the Exercise Shares, to receive the amount of Distributed Property which would have been payable to the Holder had such Holder been the holder of such Exercise Shares on the record date for the determination of stockholders entitled to such Distributed Property. The Company will at all times set aside in escrow and keep available for distribution to such holder upon exercise of this Warrant a portion of the Distributed Property to satisfy the distribution to which such Holder is entitled pursuant to the preceding sentence.

          (C) Upon the occurrence of each adjustment pursuant to this Section 4, the Company at its expense will, at the written request of the Holder, promptly compute such adjustment in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Exercise Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Company’s transfer agent.

     5. Fractional Shares. No fractional shares shall be issued upon the exercise of this Warrant as a consequence of any adjustment pursuant hereto. All Exercise Shares (including fractions) issuable upon exercise of this Warrant may be aggregated for purposes of determining whether the exercise would result in the issuance of any fractional share. If, after aggregation, the exercise would result in the issuance of a fractional share (a) the Company shall, in lieu of issuance of any fractional share, pay the Holder otherwise entitled to such fraction a sum in cash equal to the product resulting from multiplying the then-current fair market value of an Exercise Share by such fraction and (b) the number of Exercise Shares to be issued will be rounded down to the nearest whole share.

     6. Fundamental Transactions. The Company shall not enter into or be party to a Fundamental Transaction unless the Successor Entity assumes this Warrant in accordance with the provisions of this Section 6. Upon the occurrence of any Fundamental Transaction, the Successor Entity shall succeed to, and be substituted for (so that from and after the date of such Fundamental Transaction, the provisions of this Warrant referring to the “Company” shall refer instead to the Successor Entity), and may exercise every right and power of the Company and shall assume all of the obligations of the Company under this Warrant with the same effect as if such Successor Entity had been named as the Company herein. Prior to the consummation of any Fundamental Transaction pursuant to which holders of shares of Common Stock are entitled to receive securities or other assets with respect to or in exchange for shares of Common Stock (a “Corporate Event”), the Company shall make appropriate provision to insure that the Holder will thereafter have the right to receive upon an exercise of this Warrant at any time after the

consummation of the Fundamental Transaction but prior to the Expiration Date, in lieu of the Exercise Shares (or other securities, cash, assets or other property) purchasable upon the exercise of the Warrant prior to such Fundamental Transaction, such shares of stock, securities, cash, assets or any other property whatsoever (including warrants or other purchase or subscription rights) which the Holder would have been entitled to receive upon the happening of such Fundamental Transaction had the Warrant been exercised immediately prior to such Fundamental Transaction. Provision made pursuant to the preceding sentence shall be in a form and substance reasonably satisfactory to the Holder. The provisions of this Section 6 shall apply similarly and equally to successive Fundamental Transactions and Corporate Events and shall be applied without regard to any limitations on the exercise of this Warrant.

     7. No Stockholder Rights. Other than as provided in Section 3.2 or otherwise herein, this Warrant in and of itself shall not entitle the Holder to any voting rights or other rights as a stockholder of the Company.

     8. Transfer of Warrant. Subject to applicable laws and any restrictions on transfer set forth in the Purchase Agreement, this Warrant and all rights hereunder are transferable, by the Holder in person or by duly authorized attorney, upon delivery of this Warrant and the form of assignment attached hereto to any transferee designated by Holder. The transferee shall sign an investment letter in form and substance reasonably satisfactory to the Company and its counsel. Any purported transfer of all or any portion of this Warrant in violation of the provisions of this Warrant shall be null and void.

     9. Lost, Stolen, Mutilated or Destroyed Warrant. If this Warrant is lost, stolen, mutilated or destroyed, the Company may, on such terms as to indemnity or otherwise as it may reasonably impose (which shall, in the case of a mutilated Warrant, include the surrender thereof), issue a new Warrant of like denomination and tenor as this Warrant so lost, stolen, mutilated or destroyed. Any such new Warrant shall constitute an original contractual obligation of the Company, whether or not the allegedly lost, stolen, mutilated or destroyed Warrant shall be at any time enforceable by anyone.

     10. Notices, Etc. All notices required or permitted hereunder shall be in writing and shall be deemed effectively given: (a) upon personal delivery to the party to be notified, (b) when sent by confirmed facsimile to the facsimile number specified in writing by the recipient if sent during normal business hours of the recipient on a Trading Day, if not, then on the next Trading Day, (c) the next Trading Day after deposit with a nationally recognized overnight courier, specifying next day delivery, with written verification of receipt. All communications shall be sent to the Company at the address listed on the signature page hereto and to Holder at the applicable address set forth on the applicable signature page to the Purchase Agreement or at such other address as the Company or Holder may designate by ten (10) days advance written notice to the other parties hereto.

     11. Acceptance. Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

     12. Governing Law. This Warrant and all rights, obligations and liabilities hereunder shall be governed by, and construed in accordance with, the internal laws of the State

of California, without giving effect to the principles of conflicts of law that would require the application of the laws of any other jurisdiction.

     13. Amendment or Waiver. Any term of this Warrant may be amended or waived (either generally or in a particular instance and either retroactively or prospectively) with the written consent of the Company and the Holder. No waivers of any term, condition or provision of this Warrant, in any one or more instances, shall be deemed to be, or construed as, a further or continuing waiver of any such term, condition or provision.

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     In Witness Whereof, the Company has caused this Warrant to be executed by its duly authorized officer as of [___] [___], 200___.

		XENOPORT, INC.
		By:
				Name: [                    ]
				Title: [                    ]
		3410 Central Expressway
		Santa Clara, California 95051

NOTICE OF EXERCISE

TO: XENOPORT, INC.

     (1) The undersigned hereby elects to purchase [___] shares of the common stock, par value $.001 (the “Common Stock”), of XENOPORT, INC. (the “Company”) pursuant to the terms of the attached Warrant, and tenders herewith payment of the exercise price in full, together with all applicable transfer taxes, if any.

     [_] The undersigned hereby elects to purchase [___] shares of Common Stock of the Company pursuant to the terms of the net exercise provisions set forth in Section 2.2 of the attached Warrant, and shall tender payment of all applicable transfer taxes, if any.

     (2) Please issue the certificate for shares of Common Stock in the name of:

Print or type name

Social Security or other Identifying Number

Street Address

City State Zip Code

     (3) If such number of shares shall not be all the shares purchasable upon the exercise of the Warrants evidenced by this Warrant, a new warrant certificate for the balance of such Warrants remaining unexercised shall be registered in the name of and delivered to:

          Please insert social security or other identifying number:                     

(Please print name and address)

Dated:

(Date)

		(Signature)
		(Print name)

ASSIGNMENT FORM

     (To assign the foregoing Warrant, execute this form and supply required information. Do not use this form to purchase shares.)

     FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced thereby are hereby assigned to

Name:
		(Please Print)
Address:
		(Please Print)

Dated:       , 20[__]

Holder’s Signature:
Holder’s Address:

NOTE: The signature to this Assignment Form must correspond with the name as it appears on the face of the Warrant, without alteration or enlargement or any change whatever. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing Warrant.