This paper presents sequential histological, histochemical and biochemical changes in rat caput epididymis after a single 100 mg/kg oral dose of alpha chlorohydrin. Desquamation of caput epithelium occurs as early as two days after drug treatment. The caput epididymis is blocked because of accumulation of testicular fluid containing exfoliated immature testicular cells and caput epithelium. There was no effect of drug on motility and morphology of spermatozoa examined from different segments of epididymis and vas deferens. Marked decrease in acid and alkaline phosphatases, nucleic acids and proteins have been registered after drug treatment. On the contrary increase in SDH, cholesterol and glycogen was observed after drug treatment. Decrease in phospholipids in initial stages has also been observed.