Lactase is mainly used for gastrointestinal flatulence, intestinal cramps and diarrhea after eating dairy products due to lactase deficiency. Taking lactase and still having diarrhea may be due to the combination of other infections, or insufficient dosage of lactase, inaccurate diagnosis of lactose intolerance and other conditions. 1. Combined with other infections: gastrointestinal function is not perfect, lactose intolerance occurs, by supplementing lactase, it can promote the digestion of lactose and improve the symptoms of diarrhea. If you take lactase or diarrhea, may be a combination of other bacterial infections, only the application of lactase can not achieve a better therapeutic effect, you need to improve the stool routine and bacterial analysis, etc., clearly infected people can follow the doctor’s instructions for appropriate use of penicillin and other drugs for treatment. 2. Lactase dosage is insufficient: clearly lactose intolerance, after taking lactase or diarrhea, may be the degree of lactose intolerance is more serious, need to continue to use the drug or adjust the dosage under the guidance of the doctor. 3. Inaccurate diagnosis of lactose intolerance: consider whether it is gastroenteritis, especially acute infectious gastroenteritis, inflammatory infections lead to intestinal flora disorders, diarrhea, and is not caused by lactose intolerance. It is necessary to carry out rehydration, follow the doctor’s instructions to use drugs to regulate the balance of intestinal flora for treatment, such as the appropriate application of probiotics or bifidobacteria, and so on. It is recommended to consult a doctor in time for examination and clear diagnosis.