We have treated 45 patients with various degrees of oligospermia and asthenospermia with arginine, indomethacin and kallikrein. Fifteen patients have received the amino acid L-arginine hydrochloride, 15 the antiinflammatory agent indomethacin, while 15 others the enzyme kallikrein. These drugs have been administered for at least 3 months to encompass a complete cycle of spermatogenesis. As a result, treatment with these drugs has increased sperm count and motility to some extent. Three pregnancies (20%) have been obtained by arginine and one pregnancy (6.6%) by indomethacin. Though arginine offers some hope for the future, improvement of the fertilizing capacity with these drugs is still controversial.