The case includes a 7-month-old puppy poodle applied to a private hospital for weakness, tremors and seizure attacks. Clinical examination findings were normal. From blood samples, biochemical parameter measurements were carried out. The values of alkaline phosphatase (ALP), alanine aminotransferase (ALT), ammonia and fasting serum bile acids ​​were high and the blood urea nitrogen (BUN) value ​​was low. Ultrasonographic examination, shunted vein in the liver to the vena cava caudalis, that is, colour Doppler observed the extrahepatic shunt and turbulent flow in this shunted. Depending on clinical, laboratory (hemogram and biochemistry) and ultrasonographic observations, portosystemic shunt (PSS) was diagnosed and controlled one month after the treatment was recommended. The medical treatment included a hepatic formula diet (liver care), lactulose 0.5 ml/kg three times a day, metronidazole 15 mg/kg twice a day, S-adenosyl Methionine 15 mg/kg once a day, 400 international unite (IU) vitamin E once a day for 30 days. When turbulent flow is observed in the shunted vein in the liver to vena cava caudalis, ultrasound examination with color Doppler can help diagnose portosystemic shunt. After the treatment, clinical improvement was observed and clinical symptoms of hepatic encephalopathy including seizures and tremors, disappeared completely. Determination of turbulent flow with colour Doppler and decreased portal flow velocity with portal hypertension with PW-Doppler ultrasonography are important for the diagnosis of the portosystemic shunt. It was concluded that medical treatments might help before surgical treatments in portosystemic shunts.