Background: Pythiosis is caused by the agent Pythium insidiosum, an aquatic oomycete of the kingdom Stramenopila.
Aims: To describe the symptoms, pathological changes and diagnosis methods of gastric pythiosis in dogs.
Methods: A three-year-old female German shepherd, with access to wetlands, was attended due to vomiting and recurrent diarrhea of 30 days of duration.