This review described the presentation, diagnosis, and treatment of common GI diseases in ferrets, rabbits, guinea pigs, rats, and hamsters. A diagnostic plan for ferrets presenting with gastroenteritis was provided. Gastroscopy is a noninvasive tool allowing examination and collection of partial-thickness tissue samples. Common noninfectious diagnoses include inflammatory bowel disease, eosinophilic gastroenteritis, GI lymphoma, and liver disease. Infectious causes include Helicobacter mustelae, coronavirus, and Eimeria furonis. In rabbits, a focused diagnostic plan is key to achieving definitive diagnosis when GI stasis is suspected. There are various causes of obstructions (eg, pellets, hair, GI tumors). Treatment generally involves fluid therapy and pain management if surgical management is not warranted. Additional presentations reviewed included liver lobe torsions, biliary cystadenomas, astrovirus infection, and coccidiosis. Several reports of gastric dilatation–volvulus in guinea pigs have been released. Patients present with tachypnea, lethargy, anorexia, and lacking fecal production. Survey radiographs aid diagnosis, which must be differentiated from gastric stasis. Surgical correction has been unsuccessful. Rats can develop hepatic sarcoma, with Taenia taeniaeformis as a predisposing factor. Ultrasonography or radiographic imaging aids diagnosis, but treatment options are unknown. The primary agent of GI disease in hamster colonies is Clostridium difficile. Affected hamsters often die from associated diarrhea.