lactose intolerance

from the GNU version of the Collaborative International Dictionary of English.

• noun A physiological condition in which lactose cannot be hydrolyzed in the intestine, leading to uncomfortable gaseousness, cramps, or diarrhea after eating a lactose-containing food such as milk or ice cream. The symptoms may be prevented by ingesting a preparation of beta-galactosidase before or together with dairy products.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Inability to fully metabolize lactose.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun congenital disorder consisting of an inability to digest milk and milk products; absence or deficiency of lactase results in an inability to hydrolyze lactose