Used historically as an antimalarial agent, particularly during World War II when access to quinine was limited. It has also been employed in the treatment of certain parasitic infections, including giardiasis and tapeworm infestations. In medical research, quinacrine dihydrochloride has been utilized for its fluorescent properties to stain and identify cellular components, especially in cytogenetics for chromosome banding studies. It has been investigated for its potential in treating autoimmune conditions such as lupus due to its immunomodulatory effects. Additionally, it has shown in vitro activity against certain viruses and prion diseases, leading to experimental use in neurodegenerative disease research. Topical formulations have been explored for treating inflammatory skin conditions.