Abstract
An infant was presented in whom lactosuria and vomiting occurred shortly after birth when fed on a lactose-containing diet and both of them disappeared completely when fed on a lactose-free diet. Abnormal activity of lactase was not demonstrated in the intestinal mucosa, epithelial cells of buccal mucous mem-brane and hepatic cells of this infant. A possibility is, therefore, suggested that lactose intolerance w th lactosuria and vomiting as prominent features developes in the absence of a defect in lactase activity of the intestinal mucosa, and that a disorder included under the term of ‘lactose-intolerance’ should be divided into two subgroups (lactose intolerance with lactosuria and lactose intolerance without lactosuria) from view of clinical and biochemical points. This is the first report of lactose intolerance in Japan.
