FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * ROBERTS BRYAN E   2. Issuer Name and Ticker or Trading Symbol IRONWOOD PHARMACEUTICALS INC [IRWD] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O VENROCK, 3340 HILLVIEW AVENUE 3. Date of Earliest Transaction (Month/Day/Year) 03/09/2015 (Street) PALO ALTO, CA 94304 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 03/09/2015   S   148 D $ 15.62 105 I By LLC (1) Class A Common Stock 03/09/2015   S   5,992 D $ 15.63 82,270 I By Funds (2) Class A Common Stock 03/09/2015   S   508 D $ 15.63 6,975 I By Funds (3) Class A Common Stock 03/10/2015   S   105 D $ 15.07 0 I By LLC (4) Class A Common Stock 03/10/2015   S   82,270 D $ 15.17 0 I By Funds (5) Class A Common Stock 03/10/2015   S   6,975 D $ 15.17 0 I By Funds (6) Class A Common Stock               15,085 D   Class A Common Stock               33,117 I By LLC (7) Class A Common Stock               18,910 I By Funds (8) Class B Common Stock               40,000 I By LLC (9)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
ROBERTS BRYAN E C/O VENROCK 3340 HILLVIEW AVENUE PALO ALTO, CA 94304	X

Signatures

/s/ Bryan E. Roberts		03/11/2015
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Venrock Management, LLC ("VM") holds an aggregate of 105 shares of Class A Common Stock of the Issuer. Dr. Roberts is a member of VM and may be deemed to beneficially own these shares. Dr. Roberts expressly disclaims beneficial ownership over all shares held by VM, except to the extent of his indirect pecuniary interest therein.
(2)	Venrock Associates V, L.P. ("VA5") holds an aggregate of 82,270 shares of Class A Common Stock of the Issuer. Venrock Management V, LLC ("VM5") is the sole general partner of VA5 and may be deemed to beneficially own these shares. Dr. Roberts is a member of VM5 and may be deemed to beneficially own these shares. Dr. Roberts and VM5 expressly disclaim beneficial ownership over all shares held by VA5, except to the extent of their indirect pecuniary interests therein.
(3)	Venrock Partners V, L.P. ("VP5") holds an aggregate of 6,975 shares of Class A Common Stock of the Issuer. Venrock Partners Management V, LLC ("VPM5") is the sole general partner of VP5 and may be deemed to beneficially own these shares. Dr. Roberts is a member of VPM5 and may be deemed to beneficially own these shares. Dr. Roberts and VPM5 expressly disclaim beneficial ownership over all shares held by VP5, except to the extent of their indirect pecuniary interests therein.
(4)	VM holds an aggregate of 0 shares of Class A Common Stock of the Issuer. Dr. Roberts is a member of VM and may be deemed to beneficially own these shares. Dr. Roberts expressly disclaims beneficial ownership over all shares held by VM, except to the extent of his indirect pecuniary interest therein.
(5)	VA5 holds an aggregate of 0 shares of Class A Common Stock of the Issuer. VM5 is the sole general partner of VA5 and may be deemed to beneficially own these shares. Dr. Roberts is a member of VM5 and may be deemed to beneficially own these shares. Dr. Roberts and VM5 expressly disclaim beneficial ownership over all shares held by VA5, except to the extent of their indirect pecuniary interests therein.
(6)	VP5 holds an aggregate of 0 shares of Class A Common Stock of the Issuer. VPM5 is the sole general partner of VP5 and may be deemed to beneficially own these shares. Dr. Roberts is a member of VPM5 and may be deemed to beneficially own these shares. Dr. Roberts and VPM5 expressly disclaim beneficial ownership over all shares held by VP5, except to the extent of their indirect pecuniary interests therein.
(7)	Consists of 33,117 shares of Class A Common Stock of the issuer held by the VR Management, LLC (the "Management Company"). Dr. Roberts is a member of the Management Company and may be deemed to beneficially own these shares. Dr. Roberts disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.
(8)	VHCP Management, LLC ("VHCP Management") holds an aggregate of 18,910 shares of Class A Common Stock of the Issuer. Dr. Roberts is a managing member of VHCP Management and may be deemed to beneficially own these shares. Dr. Roberts expressly disclaims beneficial ownership over these shares except to the extent of his indirect pecuniary interest therein.
(9)	Consists of 40,000 shares of Class B Common Stock of the issuer held by the Managment Company. Dr. Roberts is a member of the Management Company and may be deemed to beneficially own these shares. Dr. Roberts disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.