An illness of the digestive system caused by infection with tapeworm eggs or larvae.

Taeniasis is caused by taking in the eggs or larvae of any of the three species of tapeworms in the group Taenia that can infect people. The tapeworm eggs spread in undercooked beef or pork. The eggs infect the human intestine, but infection with one particular species of Taenia tapeworm may cause illness outside the intestines.

Tapeworm infection may not cause symptoms. If it does, symptoms of infection in the intestines may include upset stomach, belly pain or weight loss. Tapeworm segments may be visible as they pass through the anus and in the stool.

Medicines that target parasites are used to treat taeniasis.