GLPG0974 is an experimental drug which acts as a reasonably potent and selective antagonist for the free fatty acid receptor FFAR2 (GPR43). It was originally developed as a potential medication for ulcerative colitis, and while it was not developed as a medicine for this application it has remained widely used as a pharmacological tool compound for research into the FFAR2 receptor, as one of the relatively few selective FFAR2 antagonists available. Despite its antagonist action, it can also act as a positive allosteric modulator of FFAR2 under some conditions, which can complicate interpretation of results obtained using GLPG0974 in the presence of other FFAR2 ligands.