Secondary lactose intolerance can be treated with lactase and probiotics. 1. Lactase: Lactose intolerance is often induced by lactase deficiency or low activity, which needs to be actively supplemented. Lactobacillus, E. coli and Bacillus can produce lactase, and lactobacillus tablets or lactase tablets can be taken. 2. Probiotics: A variety of probiotics are related to lactase, microbial preparation containing probiotics can help to promote the proliferation of small intestinal villous epithelial cells in animals, and occasionally finally alleviate diarrhea induced by secondary lactose intolerance, so it is necessary to supplement probiotic preparation, such as Bifidobacterium trilobium capsule and Bifidobacterium tetrapseudomallei tablets, and so on. Lactase, when taken in large quantities, may cause adverse effects such as slightly dry stools and intestinal flora disorders, and should not be mixed with milk powder; common adverse effects of probiotic preparations include diarrhea, abdominal pain, and allergic reactions, and are contraindicated in patients with severe immunodeficiencies and allergies to probiotics. In addition, the application of the above drugs have certain risks, it is recommended that patients need to get the guidance of a specialist.