Intestinal lymphangiectasia (IL) is a rare gastrointestinal disease that is characterized by marked dilatation of the intestinal lymphatic network. The disease affects both dogs and humans but the treatment differs between humans and dogs. Genetics of IL is not yet fully understood, heritability is likely and some genes essential for lymphangiogenesis have been isolated. The pathogenesis is relatively well studied. The treatment aim is to reduce the loss of plasma proteins. The essential of treatment is to minimize the amount of triglycerides with long chain fatty acids (LCT) in the diet since absorption of these stimulate the intestinal lymph and subsequent protein loss. The diet must also compensate for the loss of protein, energy and vitamins by having a high nutrient density and contain plenty of high-quality protein. Immunosuppressive drugs have long been a part of the treatment in veterinary medicine, although IL in many cases lacks an inflammatory component and the side effects of these drugs are counterproductive in IL. Some, but not all dogs respond to medical treatment in the form of corticosteroids. Supplementation with medium chain triglyceride (MCT-oil) is controversial and both oil palatability and absorption has been questioned. This master thesis includes a case report, study and a palatability test of MCT-oil. The results show that MCT-oil, in contrast to previous claims, is well accepted by dogs. A review of earlier studies shows that the absorption of MCT-oil is complex. In addition to the length of the fatty acids, the internal structure of the triglyceride molecule, the amount of MCT and the total fat content in the diet plays a role in the absorption of MCT. Although a small percentage is absorbed by 2 the lymphatic vessels supplementation with MCT can be of benefit in cases of dogs who cannot manage to keep the weight of only fat-reduced diet.