Medstone's Submission For Gallstones Is Filed and Panel Date Set.

ALISO VIEJO, Calif.--(BW HealthWire)--March 6, 1998--Medstone International Inc. (Nasdaq: MEDS) Friday announced that the Food and Drug Administration (FDA) informed Medstone in writing that its Pre-market Approval Application to non-invasively treat gallstones, using the company's lithotripter in conjunction with Actigall (ursodiol USP), is considered filed.

In the same letter, Medstone was informed that the FDA expects to take this submission before the Gastroenterology and Urology Device Advisory Panel on April 30, 1998.

The submission is based on an analysis of clinical trials for Actigall monotherapy and separate clinical trials for combination therapy with the company's lithotripter and Actigall. An analysis of these separate trials indicates that the combination therapy of a device and drug can speed up clearance of the gallstones and result in higher success rates when compared with drug therapy alone.

"Should the Medstone STS be approved to treat gallstones, it will be the only lithotripter approved in the U.S. to treat both renal stones and gallstones on the same equipment. This means a higher utilization of the Medstone machines already in the field and a comparative advantage in the competition for new sales," said David Radlinski, Medstone chairman and chief executive officer.

An estimated 20 million Americans have gallstones of which 2.3 million are symptomatic, resulting in approximately 421,000 surgeries each year. This compares with an estimated 1.5 million Americans with kidney stones resulting in approximately 180,000 extracorporeal shockwave lithotripsy procedures each year.

The filing with the FDA contains the request that the Medstone STS, in combination with Actigall therapy, be indicated for use in fragmenting and eliminating symptomatic, radiolucent, non-calcified gallstones less than 20 mm in maximum diameter. It is estimated that approximately 1.2 million Americans are in this group.

Medstone, as the only vertically integrated extracorporeal shockwave therapy ("ESWT") company, is focused on providing shockwave therapy of renal stones and expanding the application of ESWT to other diseases such as gallstones. (See the company's Web site on the Internet at http://www.medstone.com). -0-

This news release contains forward-looking information. The forward-looking statements are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. The matters discussed in this announcement contain forward-looking statements that involve risks and uncertainties, including the timely development and market acceptance of new products, the development and rate of growth of new markets and procedures, including the fee-for-service, the impact of competitive products, technologies and pricing, the effect and timing of relevant regulatory approvals and other risks detailed from time to time in each company's respective public disclosure filings with the U.S. Securities and Exchange Commission (SEC).

CONTACT: Medstone International Inc., Aliso Viejo

David V. Radlinski, chairman and chief executive

officer, 714/448-7700, Ext. 235