Treatment with a single ip dose of styrene (908 mg/kg) 5 h before iv injection of bromosulfophthalein (BSP) (50 mg/kg) in rats resulted in (1) a decrease (approximately 30%) in biliary flow during 10-25 min but an increase in such flow during 60-90 min after the BSP dose, (2) a delay in cumulative excretion (approximately 50%) of BSP in bile during 5-60 min (but the latter became close to the control value after 75 min, and (3) no change in plasma disappearance of BSP. The first two effects seemed to depend on the dose of styrene. After pretreatment (2 h) with styrene oxide (375 mg/kg ip), a greater diminution of bile flow (approximately 50%) and of cumulative excretion of BSP was observed during the entire 5-90 min of bile collection after BSP administration, but the plasma disappearance of BSP remained unaffected. These results suggest that intrahepatic metabolism (and not hepatic uptake) of BSP and/or its transport from liver to bile are impaired after styrene- or styrene oxide-induced liver injury.