Our Practice

AGMG is one of the most prestigious gastroenterology medical groups in Southern California and was founded by Dr. Dennis Riff in 1976. Dr. Steven Duckor and Dr. Michael DeMicco joined the practice in 1977. Presently, there are a total of five doctors working in the group. These include Drs. Riff, Duckor, DeMicco, Kevin Kuettel, and Peter Winkle. 

Book an appointment online, call our offices, or walk right in. We promise to do our best to provide you with the highest level of personalized care, safety, and comfort. 


Our physicians have been working together for more than 38 years, and serve as both Gastroenterologists serving Southern California, and as primary care doctors, as they are well skilled in the practice of internal medicine. 



All of our physicians have extensive knowledge and experience in gastroenterology and liver disease. Our commitment to research gives our patients the benefit of being able to frequently experience the therapies of tomorrow as well as the best medicine and practices of the present. 



AGMG physicians have worked on projects with all of the major pharmaceutical companies in the United States and abroad and are consulted weekly in regards to the development of new treatments for a variety of diseases. We consider our research capabilities as a way of offering our patients cutting edge, and alternative treatments unavailable elsewhere.

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