What Causes Bowel Worms?

Tapeworms, which live in the intestines, or bowels, of humans and other animals, are typically acquired through eating the raw or undercooked meat of an infected animal, as WebMD explains. Someone with tapeworms who doesn't wash his hands well after a bowel movement can transmit the parasites to food.

Humans are susceptible to six types of tapeworms, which are typically identified according to the type of animal they come from, according to WebMD. Tapeworms may cause symptoms including diarrhea, nausea, abdominal pain, weight loss and loss of appetite. If tapeworm eggs from pork travel to the brain, eyes, heart or liver, they can produce a life-threatening infection. Tapeworms are typically diagnosed with the help of a stool sample, and they are treated with oral medication.