Provided is a dual-release capsule formulation comprising bromodihydroartemisinin and an Fe2+ agent as the active pharmaceutical ingredients. The formulation comprises an enteric-coated pellet comprising bromodihydroartemisinin and an immediate release pellet comprising an Fe2+ agent encapsulated in a gastric soluble capsule. Preferred Fe2+ agents include ferrous sulphate, ferrous lactate and ferrous succinate. Bromodihydroartemisinin is an anti-cancer agent.