In the case of primary lactose intolerance, there is no cure; in the case of secondary lactose intolerance, it takes weeks to months to get better. 1. Primary lactose intolerance: This is a congenital condition in which the lactose gene has low or no expression, and diarrhea occurs after eating lactose-containing foods. This condition cannot be cured at present, and the only way to alleviate the symptoms is to eat foods that do not contain lactose. 2. Secondary lactose intolerance: This is due to damage to the intestinal mucosa caused by infection, surgical trauma, etc. The ability of the small intestine to digest lactose is reduced. If you actively treat the primary disease, most of them will gradually improve in about two weeks, and slowly get better in a few weeks to a few months. Lactose intolerance, it is recommended to actively go to the hospital to identify the cause, under the guidance of the doctor’s treatment.