Millions of Americans can’t digest a certain sugar in milk and milk products called lactose. If you’re one of them, you have lactose intolerance. The condition isn’t harmful, but it can be ...

Lactose intolerance is caused by a deficiency in lactase — the enzyme that breaks down the sugar in milk, called lactose. Common symptoms include bloating, abdominal cramps, nausea, and diarrhea. If ...