We evaluated the effects of topical instillation of mydriatics and vasoconstrictors on prostaglandin E<sub>2</sub> (PGE<sub>2</sub>) induced aqueous flare elevation in pigmented rabbits. Transcorneal diffusion of PGE<sub>2</sub> (25 µg/ml) by means of a glass cylinder produced aqueous flare elevation. Mydriatics (atropine sulfate, tropicamide, tropicamide plus phenylephrine hydrochloride, phenylephrine hydrochloride, and cyclopentolate hydrochloride) or vasoconstrictors (naphazoline nitrate and tramazoline hydrochloride) were topically administered before PGE<sub>2</sub> application. Aqueous flare was measured with a laser flare-cell meter. One or two instillations of atropine sulfate 1.0%, tropicamide 0.4%, tropicamide 0.5% plus phenylephrine hydrochloride 0.5%, phenylephrine hydrochloride 5.0%, cyclopentrate hydrochloride 1.0%, and naphazoline nitrate 0.05% did not inhibit PGE<sub>2</sub>-induced aqueous flare elevation. Tramazoline hydrochloride 0.118% inhibited significantly (p < 0.05) PGE<sub>2</sub>-induced aqueous flare elevation. It is possible that vasoconstriction may be involved partly in inhibition of PGE<sub>2</sub>-induced aqueous flare elevation by some drugs in pigmented rabbits.