Hodgkin's concern about the war in Vietnam led to her involvement in a number of organisations seeking to provide humanitarian aid. The most important of these was the Medical Aid Committee for Vietnam, of which she was made Vice-President in 1965, becoming President in 1971. There is extensive documentation of her activities within the Committee.

As President, Hodgkin visited North Vietnam in 1971 and 1974; only a little material relating to these visits survives (MS. Eng. c. 5692/8-9).