prophylactic

remedy that prevents or slows the course of an illness or disease

• “the doctor recommended several preventatives”

contraceptive device consisting of a thin rubber or latex sheath worn over the penis during intercourse

capable of preventing conception or impregnation

• “contraceptive devices and medications”

tending to ward off

• “the swastika...a very ancient prophylactic symbol occurring among all peoples” Victor Schultze

preventing or contributing to the prevention of disease

• “preventive medicine”
• “vaccines are prophylactic”
• “a prophylactic drug”