Taeniasis is an infection due to the pork or beef tapeworm (cestode) Taenia solium or Taenia saginata. Taenia solium is endemic to Mexico, Central America, South America, Asia, and Africa, whereas T. saginata is found worldwide.

Taeniasis is less commonly caused by infection with the Asian tapeworm Taenia asiatica. This organism is found in southeast Asia.

Taeniasis occurs when humans ingest the larval cyst form of the tapeworm. This is often in the setting of ingestion of undercooked meat. The adult tapeworm resides in the intestinal tract. Patients infected with T. solium will shed gravid proglottids (tapeworm segments) or eggs and may later develop cysticercosis (different than taeniasis) due to autoinfection by the earlier stage of the parasite. Taenia asiatica infection is caused by ingestion of infected pig viscera (rather than muscle as in T. solium infection).

Taenia infection is usually asymptomatic, and patients may seek evaluation after noticing proglottids in the stool. Occasionally they may have nausea or epigastric or abdominal pain. Laboratory evaluation may show eosinophilia. Diagnosis can be made by examination of stool for evidence of eggs or tapeworm segments.