Lactose intolerance in babies
Lactose intolerance in babies is very transient.
Stool reducing substance being positive means lactose intolerance.
That means those babies cannot digest milk ( lactose) .Sometimes lactose intolerance settles on its own depending on severity. Some kids can tolerate some amount of milk but not too much. So you Will have to wait to see whats tolerable for your baby.
During that time it is suggested to give formula feed lactose free ( ask doctor which formula feed is lactose free) for 2mnths and then reintroduce breast feed, by then lactase enzyme regeneration in baby gut would occur and will tolerate breast feed.