Norwegian Lundehunds are often affected by gastrointestinal disease, the most common clinical signs of which are intermittent diarrhea, vomiting, weight loss, lethargy, ascites, and subcutaneous edema of the hind legs. The most frequent laboratory changes include hypoalbuminemia (with or without hypoglobulinemia), hypocalcemia, a decrease in the serum cobalamin concentration, and an increase or decrease in the serum folate concentration, reflecting microbial synthesis or malabsorption, respectively. Histopathologic abnormalities can include chronic atrophic gastritis, intestinal lymphangiectasia, and lymphoplasmacytic enteritis. Because the underlying cause of gastroenteropathy in Norwegian Lundehunds has not been identified, treatment is symptomatic.