ARYx Therapeutics Inc. Announces $21.6 Million Private Placement -- New Funding Improves Strategic Position for Product Collaborations

ARYx Therapeutics, Inc. (NASDAQ: ARYX) today announced that it has entered into a securities purchase agreement in connection with a private placement to a group of accredited investors led by new investor New Enterprise Associates (NEA) with participation from significant existing shareholders including MPM Capital and OrbiMed Advisors LLC. Pursuant to the terms of the securities purchase agreement, ARYx will receive approximately $21.6 million in gross proceeds from the sale of 9,649,545 shares of its common stock and the issuance of warrants for the purchase of 2,894,864 additional shares of ARYx's common stock with an exercise price of $2.64 per share and having a term of five (5) years from the closing date.

The combined purchase price of a share of ARYx’s common stock and a warrant to purchase 0.30 of a share of ARYx’s common stock is $2.2375. The transaction is expected to close upon the satisfaction of the closing conditions under the securities purchase agreement. The third quarter 2008 financial results for ARYx, and an update on the clinical development of the company’s products, are contained in an accompanying press release.

Pacific Growth Equities, LLC served as the placement agent for this private placement.

Neither the shares of ARYx's common stock nor the warrants issued in connection with the private placement have been registered under the Securities Act of 1933, as amended (the "Securities Act"). Accordingly, these securities may not be offered or sold in the United States except pursuant to an effective registration statement or an applicable exemption from the registration requirements of the Securities Act. ARYx has agreed to file within 35 days after the closing one or more registration statements covering the resale of the common stock as well as the common stock issuable upon exercise of the warrants. This press release shall not constitute an offer to sell or the solicitation of an offer to buy ARYx's common stock or warrants.

About ARYx Therapeutics, Inc.

ARYx Therapeutics is a biopharmaceutical company focused on developing a portfolio of internally discovered products designed to eliminate known safety issues associated with well-established, commercially successful drugs. ARYx uses its RetroMetabolic Drug Design technology to design structurally unique molecules that retain the efficacy of these original drugs but are metabolized through a potentially safer pathway to avoid specific adverse side effects associated with these compounds. ARYx currently has four products in clinical trials: an oral anticoagulant agent for patients at risk for the formation of dangerous blood clots, ATI-5923; an oral anti-arrhythmic agent for the treatment of atrial fibrillation, ATI-2042; a prokinetic agent for the treatment of various gastrointestinal disorders, ATI-7505; and, an agent for the treatment of schizophrenia and other psychiatric disorders, ATI-9242. Please visit our web site at www.aryx.com for additional information.

Forward-looking Statements

This press release contains forward-looking statements, including, without limitation, statements with respect to the anticipated closing of the private placement. Words such as “will,” “expected,” “on or about,” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon our current expectations. Forward-looking statements involve risks and uncertainties. ARYx’s actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks associated with the satisfaction of the conditions to the closing of the private placement, as well as other risks discussed under “Risk Factors” and elsewhere in our Annual Report on Form 10-K for the year ended December 31, 2007, in our Quarterly Report on Form 10-Q for the quarter ended September 30, 2008 and our other filings with the U.S. Securities and Exchange Commission. ARYx expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein.

ARYx Therapeutics, Inc.
David Nagler, 510-585-2200 ext. 211
Vice President Corporate Affairs