The effects of pilocarpine, isoproterenol, epinephrine, timolol, acetazolamide, ouabain, and dinitrophenol on aqueous humor production were investigated in enucleated rabbit eye. The metabolic inhibitors ouabain and dinitrophenol at a concentration of 10(-5) M produced a 50% inhibition in aqueous humor formation. Acetazolamide at the same concentration was without effect, but at 10(-4) M concentration lowered aqueous production by 40%. The autonomic drugs epinephrine and isoproteranol at a concentration of 10 micrograms/ml medium reduced aqueous humor formation by 64 and 52% respectively. Timolol, even at a concentration of 0.05 microgram/ml, suppressed aqueous humor formation by approximately 30%. Pilocarpine on the other hand was ineffective. Except for pilocarpine, these responses are similar to those reported to occur in the cat both in vivo and in vitro.