Lactase has no special contraindications and can generally be taken for six months. Lactose contained in dairy products can not be directly absorbed by the human body, the human small intestine can be secreted lactase enzyme used to break down lactose, endogenous lactase secretion is insufficient will lead to lactose digestion and absorption disorders, some of them will be bloating, abdominal pain, diarrhea, mainly a series of symptoms, known as lactose intolerance. Lactase supplementation before consuming dairy products can break down the lactose ingested and improve the symptoms of lactose intolerance. Lactose intolerant patients taking lactase after diarrhea, bloating and other uncomfortable symptoms less, need to consolidate for a period of time, and then ordered to reduce the amount, need to improve the symptoms through the 2 ~ 3 months of conditioning before stopping the drug, if the recurrence of drug discontinuation, you can take long-term.