The head of the University of Tokyo Hospital, Sakae Tanaka, has resigned from his post over a series of bribery scandals involving staff at the institution.

In an official statement published on its website, the hospital said that Tanaka stepped down on Tuesday to take responsibility for the failure in hospital management that had resulted in misconduct among doctors.

The resignation follows the arrest of Shinichi Sato, a professor at the University of Tokyo¡¯s Graduate School of Medicine and a practicing doctor at the hospital¡¯s dermatology department, on Saturday.

Sato, 62, was referred to prosecutors on Monday on suspicion of accepting entertainment worth around ?1.8 million ($11,810) ¡ª equivalent to about 30 sessions at high-end clubs and brothels ¡ª from the Japan Cosmetic Association, an institute the university had been partnering with in a joint research project.

Sato had been leading the joint project on plant cannabinoids found in cannabis plants since April 2023. The club and brothel sessions for Sato allegedly took place between February 2023 and September 2024. In return for the entertainment, Sato is thought to have provided favors to the association in matters regarding the project.

On Monday, the Tokyo Metropolitan Police also sent papers to prosecutors on Ayumi Yoshizaki, a 46-year-old former specially appointed associate professor at the university, and Koichi Hikichi, a 52-year-old representative of the Japan Cosmetic Association, who are also thought to have been involved in the bribery case.

The hospital released a statement on Sunday saying it would cooperate fully with the investigation as well as work with the University of Tokyo. It said it would take appropriate action in relation to the case.

¡°Going forward, we will thoroughly instill a strong sense of compliance among all faculty and staff at our hospital and implement the necessary measures to prevent a recurrence,¡± the hospital¡¯s statement read.

In November last year, another doctor at the University of Tokyo Hospital ¡ª Takehiro Matsubara ¡ª was arrested and later indicted for allegedly receiving cash as a scholarship donation from a medical supply company in exchange for preferential treatment and using supplies from the company to perform surgery at the hospital.

Teruo Fujii, the president of the University of Tokyo, which the hospital is affiliated to, said in that the ¡°repeated arrests of faculty members are deeply regrettable,¡± as faculty and staff at national universities are expected to comply with laws and regulations, and uphold a high level of ethical standards.

Fujii also held a news conference on Wednesday evening to explain the university¡¯s next course of action in the wake of the bribery cases.