Diloxin therapy is given as a cancer treatment option to President Laura Roslin by Doctor Cottle to battle her breast cancer.
Diloxin therapy is likely a form of chemotherapy. President Roslin tells Dr. Cottle of having her mother endure two years of diloxin therapy as she wasted away, and therefore the President wanted to explore alternative treatments such as chamalla. Roslin's account of her mother's treatment suggests that the side effects of diloxin therapy (hair loss, nausea, muscle degeneration), like many chemotherapy options in the real world, may be just as debilitating and uncomfortable as the illness it is intended to cure (Act of Contrition).
When Roslin's cancer returns after apparently having been cured, she takes diloxin treatments despite her earlier aversion to the drug (Crossroads, Part II).