Helminthic diseases of the digestive system are caused by parasitic worms that infect the human intestinal tract. Common types are tapeworms, nematodes, and pinworms. Tapeworms have complex life cycles involving intermediate hosts and can cause cysts or cysticercosis if larvae infect tissues. Symptoms vary depending on the worm but may include abdominal pain, diarrhea, weight loss, and anemia. Diagnosis involves finding eggs or proglottids in stool samples or imaging tests. Treatment typically involves anthelmintic drugs like mebendazole, albendazole, or pyrantel pamoate.