Chauncey D. Leake, 81, internationally known pharmacologist, medical historian, educator and writer, died of heart failure Wednesday in San Francisco.

He had collapsed Tuesday night shortly after reading a collection of his poems at a private club.

A president in 1960 of the American Association for the Advancement of Science, Dr. Leake had worked in the fields of nervous system activity, narcotics, anesthesia, chemotherapy, geriatics, the mechanisms of drug action and the history and philosophy of health professions and science.

He was one of the early scientists to warn of the dangers of air and water pollution.

Born in Elizabeth, NJ., Dr. Leake was a graduate of Princeton University and earned master's and doctoral degrees from the University of Wisconsin, where he was an assistant professor of pharmacology from 1923 to 1928.

He then went to the University of California at San Francisco, where he organized the department of pharmacology and was a professor.

From 1942 to 1955, Dr. Leake was executive vice president in charge of the medical bureau at the University of Texas at Galveston. From there he moved to Ohio State University, where he was professor of pharmacology and then coordinator of student research learning for 10 years.

In 1965, he returned to the University of California at San Francisco as senior lecturer on pharmacology and the history and philosophy of medicine.

Over the years, Dr. Leake had lectured widely at colleges, universities and other institutions throughout the country. A prolific writer, he was the author of hundreds of medical and scientific articles and books.

He had been a consultant to the American Red Cross, the U.S. Public Health Service and the Army Medical Library. Dr. Leake belonged to numerous medical and scientific organizations. He was a member of the Cosmos Club here.

He is survived by two sons, Dr. Wilson W., of Seattle, Wash., an Chauncey D. Jr., of New York.