To evaluate the phytochemical constituents and the aphrodisiac potential of the aqueous extract of Fadogia agrestis (Rubiaceae) stem in male albino rats. The aqueous stem extract of the plant was screened for phytochemical constituents. Male rats were orally dosed with 18 mg/kg, 50 mg/kg and 100 mg/kg body weight, respectively, of the extract at 24 h intervals and their sexual behavior parameters and serum testosterone concentration were evaluated at days 1, 3 and 5. Phytochemical screening revealed the presence of alkaloids and saponins while anthraquinones and flavonoids are weakly present. All the doses resulted in significant increase in mount frequency, intromission frequency and significantly prolonged the ejaculatory latency (P 0.05) and reduced mount and intromission latency (P 0.05). There was also a significant increase in serum testosterone concentrations in all the groups in a manner suggestive of dose-dependence (P 0.05). The aqueous extract of Fadogia agrestis stem increased the blood testosterone concentrations and this may be the mechanism responsible for its aphrodisiac effects and various masculine behaviors. It may be used to modify impaired sexual functions in animals, especially those arising from hypotestosteronemia.
