Tapeworm infection is caused by eating the raw or undercooked meat of infected animals. Cattle usually carry Taenia saginata (T saginata). Pigs carry Taenia solium (T solium).

In the human intestine, the young form of the tapeworm from the infected meat (larva) develops into the adult tapeworm. A tapeworm can grow to longer than 12 feet (3.5 meters) and can live for years.

Tapeworms have many segments. Each segment is able to produce eggs. The eggs are spread alone or in groups and can pass out with the stool or through the anus.

Adults and children with pork tapeworm can infect themselves if they have poor hygiene. They can ingest tapeworm eggs they pick up on their hands while wiping or scratching their anus or the skin around it.

Those who are infected can expose other people to T solium eggs, usually through food handling.

Tapeworm infection usually does not cause any symptoms. Some people may have abdominal discomfort.

People often realize they are infected when they pass segments of the worm in their stool, especially if the segments are moving.

Tests that may be done to confirm diagnosis of an infection include:

• CBC, including differential count
• Stool exam for eggs of T solium or T saginata, or the worm itself

Tapeworms are treated with medicines taken by mouth, usually in a single dose. The drug of choice for tapeworm infections is praziquantel. Niclosamide can also be used, but this medicine is not available in the United States.

With treatment, the tapeworm infection goes away.

In rare cases, worms can cause a blockage in the intestine.

If pork tapeworm larvae move out of the intestine, they can cause local growths and damage tissues such as the brain, eye, or heart. This condition is called cysticercosis. Infection of the brain (neurocysticercosis) can cause seizures and other nervous system problems.

Contact your health care provider for an appointment if you pass something in your stool that looks like a white worm.

In the United States, laws on feeding practices and the inspection of domestic food animals have largely eliminated tapeworms.

Measures you can take to prevent tapeworm infection include:

• Do not eat raw meat.
• Cook whole cut meat to 145°F (63°C) and ground meat to 160°F (71°C). Use a food thermometer to measure the thickest part of the meat.
• Freezing meat is not reliable because it may not kill all eggs.
• Wash hands well after using the toilet, especially after a bowel movement.

Teniasis; Pork tapeworm; Beef tapeworm; Tapeworm; Taenia saginata; Taenia solium; Taeniasis

Fairley JK, King CH. Tapeworms (cestodes). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 289.

White AC, Brunetti E. Cestodes. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 325.

Updated by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.