Jack E. Kahn, 50, who retired from the Federal Trade Commission in 1980 for reasons of health and who had been active in Jewish organizations, died of hepatitis Dec. 23 at the St. Francis Hospital in Memphis, Tenn.

Mr. Kahn, who was born in Friars Point, Miss., grew up in Memphis. He attended the University of Chicago and graduated from Southwestern at Memphis. He earned a law degree at Memphis State University. He worked for a bank in Memphis and then for the Tennessee Department of Insurance and Banking in Nashville.

In 1969, he moved to Washington and went to work for the FTC. Among other things, he helped draft regulations to implement the truth-in-lending act, made a report on the insurance industry and conducted hearings on the funeral industry.

Mr. Kahn was a member of the executive committee of the Jewish Social Service Agency in Rockville and was chairman of its commission on aging. He also was counsel to the board of directors during the establishment of home health care services.

Following his retirement, he moved from Alexandria to Memphis.

Survivors include a brother, Dr. Sidney Kahn of Los Angeles.

The family suggests that expressions of sympathy be in the form of contributions to Southwestern at Memphis, 2000 North Parkway, Memphis, Tenn. 38112.