This study was designed to evaluate the aphrodisiac and spermatogenic potential of the aqueous extract of dried roots of Chlorophytum borivilianum (CB) in rats. Male Wistar albino rats were divided into four groups. Rats were orally treated with (1) Control group: distilled water; (2) CB 125 mg/kg/day; (3) CB 250 mg/kg/day; and (4) Viagra((R)) group: 4 mg/kg/day sildenafil citrate and their sexual behaviour was monitored 3 h later using a receptive female. Their sexual behaviour was evaluated on days 1, 7, 14, 21 and 28 of treatment by pairing with a pro-oestrous female rat. For sperm count the treatment was continued further in all groups except the Viagra((R)) group for 60 days. At 125 mg/kg, CB had a marked aphrodisiac action, increased libido, sexual vigor and sexual arousal. Similarly, at the higher dose (250 mg/kg) all the parameters of sexual behaviour were enhanced, but showed a saturation effect after day 14. On day 60 the sperm count increased significantly in both the CB groups, 125 mg/kg and 250 mg/kg, in a dose dependent manner. Thus, roots of Chlorophytum borivilianum can be useful in the treatment of certain forms of sexual inadequacies, such as premature ejaculation and oligospermia. Copyright (c) 2008 John Wiley & Sons, Ltd.