Ponazuril is an antiprotozoal agent, specifically a triazine anticoccidial used in veterinary pharmacological research. It is effective against the apicomplexan group of organisms. It was originally developed to treat Sarcocystis neurona infections in horses, a parasite causing a neurological disease known as equine protozoal myeloencephalitis (EPM). It has also shown effectiveness against Theileria equi, and Toxoplasma gondii.