Pamoic acid disodium salt, a supposedly inactive component in many formulations of drugs used to modulate release, is a potent agonist of the orphan receptor GPR35. GPR35 is a class A, rhodopsin-like G protein-coupled receptor (GPCR), strongly expressed in the lower intestine and colon, dorsal root ganglia, as well as a variety of immune cells including monocytes and dendritic cells. Targeting GPR35 provides potential therapeutic opportunities in a range of conditions, such as inflammation, pain and cancer.