The medical records of 33 horses aged between 3.5 and 9 years suffering from serum hepatitis were reviewed. Serum hepatitis in horses was clinically manifested by mental depression related signs in most of the affected horses including dullness, depression, lethargy, compulsive walk, and hyporeflexia. Other cases showed mental irritation related signs including hyperexcitability, muscle tremors and convulsions. The majority of horses were completely anorexic, enduring acute abdominal pain. The clinical examination revealed congested mucus membranes, tachypnea, tachycardia, abdominal distention and photosensitization. The blood picture revealed anemia, leukocytosis, and neutrophilia with regenerative shit left shift. Serum biochemistry revealed hypopreteinemia, hypoalbuminemia, hypoglycemia and increased activity of serum aspertate aminotranferase, Gama glutamyle transferase, alkaline phosphatase, increased total bilirubin and increased prothrombin time. All horses were treated with non-sterooidal anti inflammatory; 24 of which reccived as well corticosteroids. Special care were also trialed, including lactated ringers, dextrose 5% solutions, and neomycin. To control the nervous signs Xylazine was indicated. Most of the horses were treated for more than 5 days. Fifteen out of the 33 examined horses rapidly died few hours from the onset of the clinical signs, while nine were euthanatized shortly before death because of their deteriorated condition. The postmortem examination of the fifteen horses revealed ruptured liver capsule, severe internal hemorrhages and friable liver parenchyma, theother nine cases showed hepatomegally without rupture of the liver capsule. The histopathological examination of the liver tissues showed massive subcapsular hemorrhages with granulation tissue