Cocaine (benzoylmethylecgonine) (INN) is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" and the alkaloid suffix -ine, forming cocaine. It is a stimulant, an appetite suppressant, and a topical anesthetic. Biologically, cocaine acts as a serotonin–norepinephrine–dopamine reuptake inhibitor, also known as a triple reuptake inhibitor (TRI). It is addictive because of its effect on the mesolimbic reward pathway.
Unlike most molecules, cocaine has pockets[clarification needed] with both high hydrophilic and lipophilic efficiency, violating the rule of hydrophilic-lipophilic balance. This causes it to cross the blood–brain barrier far better than other psychoactive chemicals and may even induce blood brain barrier breakdown.