Diarrhea after taking lactase may be related to the severity of the condition, improper application and other factors. 1. Serious condition: Lactase is mainly used for abdominal distension, diarrhea and other discomforts caused after consuming dairy products due to the lack of glycoenzymes. The patient’s condition is so serious that after taking the medicine, the effect cannot be seen quickly, and the symptoms of continuous diarrhea can appear. 2. Improper application: If the application dose is insufficient, it can affect the effectiveness of the drug, which in turn leads to the symptoms of diarrhea after using the drug. 3. Other factors: If the diagnosis is inaccurate, diarrhea is caused by intestinal flora imbalance, food poisoning, or lactose intolerance combined with bacterial infections caused by diarrhea, it is difficult to cure diarrhea and other diseases by applying lactase alone. This symptom should be taken seriously, and timely medical examination should be carried out, and intervention should be made according to the results of the appropriate tests.