 Mani sub-study 1. A single centre open-label prospective non-comparative pharmacokinetic study will be carried out at the Department of Pharmacology Therapeutics, Makerere University College of Health Sciences, at Mulago Hospital Complex, Kampala, Uganda. Study will include children less than 5 years, n70 diagnosed with uncomplicated falciparum malaria destined to receive standard fixed-weight-based six-dose regimen of artemether-lumefantrine for 3 days on outpatient basis . A full population pharmacokinetic design will be employed to obtain sparse venous plasma samples from participants at scheduled periods during a 28 day follow up period. Each participant will provide between 1 to 8 samples during the 28 day follow up period. Venous plasma levels of lumefantrine L and its metabolite desbutyl-lumefantrine DL will be determined using liquid chromatography and mass spectrometry tandem LCMSMS at the Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden. Outcome variables will be pharmacokinetic PK exposure parameters of L and DL. Sparse PK data will be pooled for evaluation of both individual and population PK parameter estimates of lumefantrine using NONMEM. Impact of patients explanatory variables on PK parameters will be assessed. Secondary outcomes will include be adverse events and day 28 treatment outcome. 