Ulcerations in the dog's digestive system are considered rare. In this paper are described two cases of the gastroduodenal ulcer in dogs. The first animal showed ulcer in the proximal duodenum. In the second animal the ulcer was perfured and localized in the pyloric region of the stomach. The lesions were round and deep, but did not reveal evidence of bleeding. In these cases there were no other diseases.
ulcer; ulceration; digestive system; dog