The modified fasting therapy(MFT) of traditional korean medicine uses very low calorie diet on a patient with chroic disease and obesity. During the fasting period of MFT, calorie intake is restricted under 600kcal. Adverse events such as hunger, heartburn, headache, and hair loss can occur because of fasting. In case of Gilbert`s syndrome, Jaundice can arise without disorder of liver function and hemolysis because of increase of unconjugated bilirubin. We experienced a case of Gilbert`s syndrome patient who appeared jaundice during the fasting period, so we report about that with litrerature review.