[The clinical study of gossypol in 8,806 men].

For 7 years the clinical aspects of gossypol have been studied in 8806 male volunteers. Its antifertility effect is definite. The optimal oral dosage of gossypol has been found to be 20 mg/day. When the dose had been taken for a period of 75 days, 98.48% of the volunteers became infertile. With the optimal maintenance dose of 40-50 mg/week, the contraceptive effect was maintained in 99.07%. In the 75 days' period, side effects encountered were gastrointestinal symptoms in 4.15% of the volunteers and fatigue in 12.61%.