p-Hydroxyamphetamine (4-hydroxyamphetamine, α-methyltyramine) is a drug that stimulates the sympathetic nervous system. When used in eye drops, it dilates the pupil. It is sold in combination with tropicamide under the brand name Paremyd®. It occurs as a metabolite of amphetamine. Once thought to be a human invention, p-hydroxyamphetamine is now known to occur as an alkaloid in plants including Acacia berlandieri.