L-Atabrine dihydrochloride (quinacrine dihydrochloride) is primarily used as an antimalarial agent to treat and prevent malaria infections by interfering with the growth of Plasmodium parasites in red blood cells. It is also effective against other parasitic infections, including giardiasis, tapeworm, and liver fluke (e.g., Clonorchis sinensis). Additionally, it treats autoimmune disorders like lupus erythematosus due to its anti-inflammatory properties. It serves as a diagnostic tool for liver and bile duct conditions, such as biliary atresia. In research, it studies cellular mechanisms like autophagy and lysosomal function, leveraging its fluorescence under ultraviolet light, and drug interactions.