FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF 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

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(Print or Type Responses)

1. Name and Address of Reporting Person *   Gullans Steven R. Ph.D. 2. Date of Event Requiring Statement (Month/Day/Year) 03/19/2013 3. Issuer Name and Ticker or Trading Symbol TETRAPHASE PHARMACEUTICALS INC [TTPH] (Last) (First) (Middle) 800 BOYLSTON ST., SUITE 2825 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) BOSTON, MA 02199 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 Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series C Convertible Participating Preferred Stock	  (1)	  (2)	Common Stock	972,384 (1) (3)	$ (1)	I	By Excel Medical Fund, L.P. (3)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Gullans Steven R. Ph.D. 800 BOYLSTON ST. SUITE 2825 BOSTON, MA 02199	  X	  X	Â	Â

Signatures

/s/ Steven Gullans		03/19/2013
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(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)	Convertible into Common stock on a 1-for-29 basis without payment of further consideration. Each share will automatically convert into 1/29th of a share of Common Stock upon the closing of the Issuer's initial public offering.
(2)	Not Applicable.
(3)	Held by Excel Medical Fund, L.P. Excel Medical Ventures, LLC is the general partner of Excel Medical Fund, L.P. Steven R. Gullans is a Managing Director of Excel Medical Ventures, LLC. Mr. Gullans may be deemed to share voting and dispositive power with respect to all shares held by Excel Medical Fund, L.P. Mr. Gullans disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein.

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