Tapeworms are large, flat parasitic worms that live in the intestinal tracts of some animals. Types of tapeworms are known to infect humans; Tapeworm infection in people usually results from eating undercooked foods from infected animals. Tapeworm infections are treated with oral medication. Tapeworms have no digestive, respiratory, or circulatory systems, and do not own a heart to produce blood on their own. Tapeworms survive by feeding off their host’s digestive system, and absorb the nutrients that have been processed by their hosts. Independently, these worms cannot survive, so the only function they can carry is to reproduce hundreds of eggs at a time.