Ponazuril (INN), sold by Merial, Inc., now part of Boehringer Ingelheim, under the trade name Marquis® (15% w/w ponazuril), is a drug currently approved for the treatment of equine protozoal myeloencephalitis (EPM) in horses, caused by Sarcocystis neurona. More recently, veterinarians have been preparing a formulary version of the medication for use in small animals such as cats, dogs, and rabbits against coccidia, an intestinal parasite. Coccidia treatment is far shorter than treatment for EPM. Ponazuril (INN), sold by Merial, Inc., now part of Boehringer Ingelheim, under the trade name Marquis® (15% w/w ponazuril), is a drug currently approved for the treatment of equine protozoal myeloencephalitis (EPM) in horses, caused by Sarcocystis neurona. More recently, veterinarians have been preparing a formulary version of the medication for use in small animals such as cats, dogs, and rabbits against coccidia, an intestinal parasite. Coccidia treatment is far shorter than treatment for EPM.