Diethylcarbamazine citrate is primarily used in the treatment of certain parasitic infections, particularly those caused by filarial worms. It is highly effective against lymphatic filariasis, commonly known as elephantiasis, and is also used to treat tropical pulmonary eosinophilia. The medication works by immobilizing the microfilariae and altering their surface structure, making them more susceptible to destruction by the host's immune system. Additionally, it is employed in the management of loiasis, caused by the Loa loa worm, and can be used in some cases of onchocerciasis, though with caution due to potential severe inflammatory reactions. Diethylcarbamazine citrate is often administered as part of mass drug administration programs in endemic regions to reduce the burden of these diseases. Its use is typically guided by healthcare professionals to ensure proper dosing and monitoring for adverse effects.