Embelin has been shown to have potential for fertility regulation in male mammals. To further investigate this the effect of varying doses of embelin administered through different routes on plasma testosterone levels in sexually mature male white New Zealand rabbits was studied. An intramuscular injection of 5 mg/kg body weight of embelin caused a 54% declined in testosterone levels from 8.35 Β± 0.4 nmol (pre-treatment) to 3.8 Β± 0.15 nmol/L (post-treatment); mean Β± SEM. When orally administered as a suspension of 10 mg/kg body weight embelin caused a significant (p < 0.001) lowering in the hormone levels from 12.2 Β± 0.70 nmol/L (pre-treatment) to 4.55 Β± 0.35 nmol/L after treatment. But when administered orally as a 50 mg base tablet, a decline of 40% in testosterone levels was observed. Subcutaneous administration of 20 mg/kg body weight of embelin caused a 12.4% decline in the hormone levels from 26.6 Β± 1.30 nmol/L (pre-treatment) to 18.9 Β± 1.30 nmol/L after treatment. The decline in the testosterone levels when embelin was administered either intramuscularly or as a suspension orally was rapid, while a tablet or subcutaneous injection caused a gradual decline. From the study it was concluded that oral administration offered the most effective and convenient route of delivery of embelin.