Niclosamide 500 mg is an oral anthelmintic used to treat tapeworm infections such as beef (Taenia saginata), pork (Taenia solium), fish (Diphyllobothrium), and dwarf tapeworm (Hymenolepis). It acts within the intestinal lumen and is not effective for roundworms or pinworms. Common effects include nausea, vomiting, abdominal discomfort; dosing is typically a single-day regimen with a light meal and laxative per clinician guidance.