Eflornithine is primarily used in the treatment of African trypanosomiasis, also known as sleeping sickness, caused by Trypanosoma brucei gambiense. It is particularly effective in the second stage of the disease when the parasite has crossed the blood-brain barrier. The drug works by inhibiting ornithine decarboxylase, an enzyme essential for the replication of the parasite, thereby slowing its growth and proliferation.

In addition to its antiparasitic applications, eflornithine is also used in dermatology as a topical cream to reduce unwanted facial hair in women, a condition known as hirsutism. The cream works by inhibiting the same enzyme in hair follicles, which slows down hair growth and results in finer, less noticeable hair over time.

Overall, eflornithine serves as a critical therapeutic agent in both systemic and topical treatments, addressing serious parasitic infections and cosmetic concerns effectively.