Infant lactose intolerance is mainly due to the lack of lactase in the intestine, which leads to the baby's inability to absorb lactose in heavy milk powder or milk, and eventually leads to diarrhea. As for the mother's diet, there is actually no limit, because the mother's diet has no effect on the baby. Mom should take the baby to the hospital for lactose tolerance test first. If the baby is diagnosed with lactose intolerance, it should not use lactose-containing milk powder or breast milk, and can give the baby lactose-free milk powder. If the baby is breast-fed, the mother can eat lactase properly before breast-feeding and eat less foods containing lactose.