This is a randomised two arm study, comparing artemether-lumefantrine 3 days and 5 days treatment. Patients will be randomised in blocks of ten to one of the two treatment arms. The standard regimen is twice daily for three days with a delay of at least eight hours between the first and second doses. A single of primaquine will be given to all patients on the first day of treatment for gametocytocidal activity. The initial treatment will be given under supervision, all other subsequent doses will be given to the patient to the taken at home. Patients will be followed up for nine visits over forty two days.