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 * Hecht Peter M   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 __X__ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) C/O IRONWOOD PHARMACEUTICALS, INC., 301 BINNEY STREET 3. Date of Earliest Transaction (Month/Day/Year) 03/09/2016 (Street) CAMBRIDGE, MA 02142 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 B Common Stock 03/09/2016   M   220,790 A $ 1.56 4,710,322 D   Class B Common Stock 03/09/2016   S(1)   40,000 D $ 10.87 (2) 4,670,322 D   Class B Common Stock 03/10/2016   M   40,000 A $ 1.56 4,710,322 D   Class B Common Stock 03/10/2016   S(1)   40,000 D $ 10.63 (3) 4,670,322 D   Class B Common Stock 03/11/2016   M   40,000 A $ 1.56 4,710,322 D   Class B Common Stock 03/11/2016   S(1)   40,000 D $ 10.66 (4) 4,670,322 D   Class A Common Stock               4,850 I The 2000 Trust for Malcolm Paul Hecht (5) Class A Common Stock               4,850 I The 2000 Trust for Zoe Niovi Hecht (5) Class A Common Stock               4,850 I The 2000 Trust for Alexis Mae Hecht (5)

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

Employee Stock Option (Right to Buy)

$ 1.56

03/09/2016

M

220,790

(6)

03/14/2016

Class B Common Stock

220,790

$ 1.56

80,000

D

Employee Stock Option (Right to Buy)

$ 1.56

03/10/2016

M

40,000

(6)

03/14/2016

Class B Common Stock

40,000

$ 1.56

40,000

D

Employee Stock Option (Right to Buy

$ 1.56

03/11/2016

M

40,000

(6)

03/14/2016

Class B Common Stock

40,000

$ 1.56

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Hecht Peter M C/O IRONWOOD PHARMACEUTICALS, INC. 301 BINNEY STREET CAMBRIDGE, MA 02142	X		Chief Executive Officer

Signatures

/s/ Halley Gilbert, Attorney-in-Fact		03/11/2016
**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)	This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person and was made to cover the tax liabilities arising out of the exercise of stock options of the issuer reported on this form. In order to effect the sale, these shares of Class B Common Stock were converted into shares of Class A Common Stock in accordance with the issuer's certificate of incorporation.
(2)	The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.68 to $11.29, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.
(3)	The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.46 to $11.06, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.
(4)	The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.50 to $10.83, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.
(5)	These shares are held in the referenced trust for the benefit of the reporting person's child. The reporting person's spouse is the trustee of this trust. The reporting person disclaims beneficial ownership of these securities, and the filing of this report is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or any other purpose.
(6)	The option vests upon the earlier of (i) the issuer's achievement of certain regulatory, commercial and market capitaliztion milestones and (ii) January 1, 2016. Upon achievement of a regulatory milestone on October 24, 2011 and a commercial milestone on December 21, 2012, the option vested as to 400,000 and 300,000 shares of Class B Common Stock, respectively. The remainder of the option vested on January 1, 2016.

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.