Excessive protein intake can cause hepatic encephalopathy (HE). Restricting protein in HE is becoming a controversy, because it can worsen malnutrition. This article reports the case of an under nourishment HE which is treated with L-ornithine-L-aspartate (LOLA) and given appropriate diet according to the nutrition status. A 62-year-old man came with chief complaint of having reduced consciousness since 6 hours before admission. He had been diagnosed as liver cirrhosis for 6 years. Several days prior to admission he took high protein diet. Physical examination revealed under nutrition and unconsciousness. Hepatic encephalopathy was confirmed with low critical flicker test (CFF), and high blood ammonia level. He was treated with adequate diet and LOLA to decrease blood ammonia and improve the CFF. During the treatment, consciousness improved to normal, CFF increased and ammonia level decreased. In this case, the HE was treated with LOLA without protein restriction. The HE improvement, in this circumstance may be caused of LOLA treatment that helps decrease the plasma ammonia level. Adequate diet, 35-40 kcal/kgBW/d and protein intake 1.5 g/kgBW/d, has been administered safely to this patient with stage II hepatic encephalopathy. LOLA seemed to be effectively reduced ammonia level and improved the encephalopathy.