There is limited pharmacokinetic data available for the combination artesunate + amodiaquine, which is used widely to treat uncomplicated malaria. This study examines the bioavailability and tolerability of a fixed (200 mg artesunate + 540 mg amodiaquine) and loose (200 mg + 612 mg) combination with a 2x2 cross-over design in 24 healthy volunteers.