Laqueur is remembered for his research of physostigmine, a chemical substance found in the Calabar bean (Physostigma venenosa) of West Africa. In 1876 he published Ueber eine neue therapeutische Verwendung des Physostigmin, suggesting the use of physostigmine for the treatment of glaucoma . Laqueur noticed that extracts of the Calabar bean significantly lowered intraocular pressure. He could attest to these results first-hand, because Laqueur suffered from glaucoma, a fact that was kept secret from his medical colleagues until after his death.
