Lactose intolerance is a condition in which the body is unable to fully digest lactose, a form of natural sugar found in milk. Lactose intolerance is not the same thing as a food allergy and is a relatively common condition. It is more common in Native Americans and people of Asian, African, and South American descent than among people of European ancestry. The condition results from a deficiency of lactase, an enzyme made in the small intestine that breaks down lactose. Symptoms occur when an affected person consumes milk or dairy products. Symptoms and signs can include
- abdominal pain,
- bloating,
- vomiting (throwing up),
- diarrhea, and
- gas.
The degree or severity of symptoms can vary among affected people.
Other lactose intolerance symptoms and signs
- Abdominal Cramping
- Abdominal Distension
- Abdominal Pain
- Bloating
- Diarrhea
- Gas
- Gurgling Sounds in the Abdomen
- Loose Stools
- Nausea
- Vomiting
Main Article on Lactose Intolerance Symptoms and Signs

SLIDESHOW
Super Tips to Boost Digestive Health: Bloating, Constipation, and More See SlideshowPictures, Images, Illustrations & Quizzes
-
Digestive Disorders: Worst Foods for Digestion
Discover which foods to avoid in order to prevent diarrhea and digestive problems. Find out which foods can trigger diarrhea and...
-
Stomach Pain Quiz: Nausea & Other Causes
Tummy Troubles? Get a better idea of what's causing the nausea, vomiting, bloating, gas, constipation, diarrhea, pain, and other...
-
Super Tips to Boost Digestive Health: Bloating, Constipation, and More
Upset stomach? Some foods may be the culprits, and bad habits may be to blame. Treat your body right with these simple nutrition...
From 
Digestive Disorders Resources
Health Solutions From Our Sponsors
Subscribe to MedicineNet's General Health Newsletter
By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.