The study was to investigate the effect of soya bean on the absorption of pefloxacin when given by oral route in rats. The first group of animals feeding on standard pellet feeds was given pefloxacin (8 mg/kg, p.o), while the second and third groups were also given the drug at the same dosage level but were fed with 50 % and 100 % soya bean respectively. Plasma samples were collected at different time intervals following drug administration. The concentrations of pefloxacin in plasma were determined using spectrophotometric method. Feeds with 50 % and 100 % soya bean respectively, gave significant increase (P