We strive to provide personalized medical care.

About Us


The Onishi Clinic (Onishi Iin in Japanese) for internal medicine was established in the Asakusa area (central part of Tokyo) in 1892 by Dr. Usaku Onishi. The clinic moved to the Omori area in 1930 by Dr. Tai Onishi, in the southern part of Tokyo. At first, it was a proctology clinic because Dr. Tai Onishi was a surgeon with a specialty in proctology. But since Dr. Taiji Onishi, a dermatologist, became the director, the clinic started accepting not only dermatology but also general patients to serve better as a clinic to the community.

Our offerings expanded to include laser surgery and cosmetic dermatology after Dr. Yauhiko Onishi became the third director of the clinic. Our goal is to offer the newest and most appropriate medical treatments for all of our patients. We also accept general patients who have diabetes, high blood pressure, high cholesterol and other medical conditions. We do everything we can to make you feel at home when you come in for a medical consultation. Please feel free to come to the clinic and express your questions or concerns about any medical conditions.


  • Dr. Mayumi Onishi, M.D. , Ph.D.
    Director : Internal medicine, Hematology
  • Dr. Masako Ichikawa, M.D.
  • Dr. Yuko Toma, M.D. , Ph.D.
  • Dr. Keiko Ishii, M.D.
    Plastic surgery


  • 1892 Dr. Usaku Onishi opened a clinic of internal medicine in Asakusa
  • 1930 Dr. Tai Onishi opened a clinic of proctology in Omori
  • 1962 Dr. Taiji Onishi became the director and the clinic started accepting general patients
  • 1989 Build the current clinic building
  • 1999 The medical corporation Taiseikai was established
  • 2003 Dr. Yasuhiko Onishi became the director
  • 2006 Dr. Mayumi Onishi became the director

Successive directors

Tai Onishi

Taiji Onishi

Yasuhiko Onishi

Mayumi Onishi

Related hospitals

• Toranomon Hospital
• The University of Tokyo Hospital
• Toho University Omori Medical Center
• Tokyo Metropolitan Hiroo Hospital
• Tokyo Rosai Hospital
• Omori Red Cross Hospital
• Showa University Hospital
• NTT Medical Center Tokyo and …etc.