The present investigation was designed to study the spermicidal activity or lidocaine, a membrane stabilizer, and its combination with 2',4'-dichlorobenzamil hydrochloride, a Na⁺-Ca²⁺ exchange inhibitor, on human semen and spermatozoa separated from semen. Both drugs per se produced dose- and time-dependent reduction in motility of ejaculated human sperm. Lidocaine was found to potentiate the spermicidal activity of benzamil resulting in significant decrease in time for producing complete loss of ejaculated sperm motility. Sperm revival test revealed irreversible loss of sperm viability indicating a spermicidal rather than spermiostatic action by both the drugs. Furthermore, both benzamil (10-40 mM) per se and benzamil -lidocaine combination (0.5 and 16 mM) produced contraception in rabbit model.