When lactose is not completely digested, it ferments in the intestine and causes mild to severe nausea, cramps, gas, bloating and diarrhea.
Experts hesitate to call lactose intolerance a disorder because it is so common.
There is no treatment, per se, for lactose intolerance. Preventive measures include Using enzyme supplements or lactose-free substitutes. Consuming only small amounts of dairy products. Avoiding dairy products altogether.