How do in know if my child is lactose intolerant?

Gas and diarrhea: Lactose intolerance is the result of an inability to digest the sugar lactose. The consequence is excess gas, bloating, diarrhea, and abdominal discomfort or pain after eating a lactose containing food (milk, soft cheese, ice cream, whipped cream, etc).

Diarrhea, bloating: Generally, a person will get abdominal cramps, gassiness and diarrhea after consuming milk products, including milk, cheese and ice cream. Severity varies.