Pamoic acid, also called embonic acid, is a 2-Naphthoic acid derivative. Salts and esters of pamoic acid are known as pamoates or embonates. It can be prepared by the reaction of 3-hydroxy-2-naphthoic acid with formaldehyde. Pamoic acid has agonist activity for the orphan G protein-coupled receptor GPR35 by which it activates ERK and beta-arrestin2, and causes antinociceptive activity.