3Alpha,5beta-Tetrahydrocortisol (THF) was administered topically and intracamerally to ocular normotensive cynomolgus monkeys to determine whether it affects outflow facility. Monkeys received THF either topically at a dose of 2 x 5 microl drops of 300 microg/10 microl twice daily for 4 days (n = 4) or 3 times daily for 10 days (n = 4) with 10% DMSO as vehicle to the control eye, or intracamerally via 2 ml anterior chamber (AC) exchange of 30 microg/ml THF with vehicle, 0.1% DMSO, to the control eye followed by a second AC exchange using 300 microg/ml THF with vehicle to the control eye. Outflow facility was measured by a two-level constant pressure AC perfusion after administration of eye drops or after baseline outflow facility measurement and AC exchange with THF solution. The results showed no effect on outflow facility in normotensive cynomolgus monkeys.