This study investigated if soy is a better source of protein for a low-protein diet than poultry in dogs with non-operable dogs with congenital portosystemic shunt. They enrolled 16 dogs that received each diet for 4 weeks in different order, and body weight, body condition, hepatic encephalopathy score and blood tests including liver function and coagulation tests were measured at the start and end of each diet trial period. Hepatic encephalopathy improved with both diets. However, plasma NH3 and coagulation parameters were significantly better with the soy-based diet, suggesting a better support for liver function.