Six healthy volunteers were given a standard regimen of bromazepam (Lexotan) (6 mg t.d.s.) for five days. Compliance with the study protocol was demonstrated by measuring drug concentrations at steady state. Steady-state levels of 3-hydroxybromazepam were also determined. These were found to be much lower than the concentrations of bromazepam. Since the metabolite is known to be less active than the parent drug, it is likely that the metabolic will contribute little to the pharmacological effects of the drug in humans. Antipyrine pharmacokinetics were studied immediately before bromazepam administration was started, after the dosing schedule had been completed and one week after dosing had been discontinued. There were no significant changes in the disposition of antipyrine on any occasion. Therefore, although previous studies have demonstrated enzyme induction in laboratory animals given high doses of bromazepam, similar effects are unlikely to occur in humans being treated with therapeutic doses of the compound.