Treatment of MLH3 (−/− and −/+) mice with Liuweidihuang wan, classical prescriptions for Yin deficiency, partly ameliorates the body constitution of Yin deficiency in MLH3 (−/+) mice, but not in MLH3 (−/−) mice. This evidence concerns the gene MLH3 and hyperinsulinemic hypoglycemia, familial, 4.