Niclosamide is primarily used as an anthelmintic drug to treat tapeworm infections. It works by inhibiting oxidative phosphorylation in the mitochondria of the parasite, leading to energy depletion and death of the worm. The drug is effective against various species of tapeworms, including Taenia saginata, Diphyllobothrium latum, and Hymenolepis nana. Beyond its antiparasitic use, niclosamide has shown potential in other therapeutic areas. It has been investigated for its antiviral properties, particularly against certain RNA viruses. Research also highlights its role in cancer treatment due to its ability to modulate multiple signaling pathways, such as Wnt/β-catenin, NF-κB, and mTOR, which are involved in tumor growth and survival. Additionally, niclosamide has demonstrated antibacterial effects, especially against biofilm-forming bacteria like Staphylococcus aureus. It is being explored for repurposing in metabolic disorders, as it activates AMP-activated protein kinase (AMPK), influencing cellular energy homeostasis. Due to its broad biological activity and safety profile, niclosamide is a candidate for drug repurposing in oncology, infectious diseases, and metabolic conditions.