Lactose intolerance

Lactose intolerance, also called lactase deficiency, means you aren't able to fully digest the milk sugar (lactose) in dairy products. It's usually not dangerous, but symptoms of lactose intolerance can be uncomfortable.

A deficiency of lactase — an enzyme produced by the lining of your small intestine — is usually responsible for lactose intolerance. Many people have low levels of lactase, but only those who also have associated signs and symptoms have, by definition, lactose intolerance.

You can control symptoms of lactose intolerance by carefully choosing a diet that limits dairy products.

Symptoms Causes Risk factors

The signs and symptoms of lactose intolerance usually begin 30 minutes to two hours after eating or drinking foods that contain lactose. Common signs and symptoms include:

  • Diarrhea
  • Nausea, and sometimes, vomiting
  • Abdominal cramps
  • Bloating
  • Gas

Symptoms are usually mild, but may sometimes be severe.

When to see a doctor

Make an appointment with your doctor if you or your child has any signs or symptoms that worry you.

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