Clinical results have proved that this drug is well tolerated by dogs, even though side effects might occur in rare cases. Stomach and intestinal ulcers, bleeding, dark stools, peritonitis, vomiting etc., are some of the common side effects. A few of these could be life threatening as well. Piroxicam can hamper the smooth functioning of kidneys which might lead to papillary necrosis. Piroxicam could also damage the natural blood clotting mechanism, thereby increasing the risks of bleeding.