Coccidia are parasites that are often misunderstood in pets. After the first exposure, coccidia parasites are always present in the pet's intestines, and they're just waiting to take advantage of any digestive upset. It is rarely the initial cause of the diarrhea, but once diarrhea starts, the coccidia will overgrow to large numbers to keep the diarrhea going. Treat your pets with our selection of coccidia medications.