Preliminary studies have supported the background efficacy of local standard anti-malarial medications in the treatment of uncomplicated knowlesi malaria, however there are no current WHO treatment guidelines for this infection. There are both health cost benefits to a more rapidly acting agent, and due to difficulties with microscopic identification there may be more effective treatment for all malaria species if an aligned treatment guideline could be supported. We are currently conducting a separate RCT using a similar protocol evaluating artesunate-mefloquine versus chloroquine for uncomplicated P. knowlesi malaria. However artemether-lumefantrine should also be compared against chloroquine due to the fact it is also a first line anti-malarial recommended in Malaysia, and there are potential differences in efficacy due to the different administration, absorption and half-life of artemether-lumefantrine.