Lactose intolerance is the inability to fully digest the sugar (lactose) found in milk.
After eating or drinking dairy products, affected people experience diarrhea, gas, and bloating. The condition, also known as lactose malabsorption, is usually harmless, but the symptoms can be bothersome.
Lactose intolerance is caused by a lack of absorption of lactose. Lactose malabsorption occurs when your small intestine produces insufficient lactase (the enzyme that breaks down lactose) and is unable to digest all of the lactose we consume. Lactose that hasn't been digested makes its way to your colon.