Background Unit-dose packaging of antimalarial drugs may improve malaria cure by making it easier for patients to take their treatment correctly. Objectives To summarize the effects of unit-dose packaged treatment on cure and treatment adherence in people with uncomplicated malaria. Search strategy We searched the Cochrane Infectious Diseases Group Specialized Register (November 2004), CENTRAL (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to November 2004), EMBASE (1980 to November 2004), LILACS (November 2004), conference proceedings, and reference lists of articles. We also contacted pharmaceutical companies, organizations, and researchers in the field. Selection criteria Randomized controlled trials (RCTs), cluster-RCTs, quasi-RCTs, and controlled before-and-after studies of unit-dose packaged drugs for treating uncomplicated malaria. Data collection and analysis We independently assessed study eligibility and methodological quality, and extracted data for an intention to treat analysis, where possible. We combined binary data using relative risk (RR) and the fixed-effect model, and presented them with 95% confidence intervals (CI). We attempted to contact study authors for additional information. Main results Three quasi-RCTs (895 participants) and one cluster-RCT (6 health facilities) met the inclusion criteria. Trials were of poor methodological quality, and none adequately assessed treatment failure. Unit-dose packaged drugs (in conjunction with prescriber training and patient information) appeared to be associated with higher participant-reported treatment adherence in all trials. A meta-analysis of two trials (596 participants) showed that participant-reported treatment adherence was higher with blister-packed tablets compared with tablets in paper envelopes (RR 1.18, 1.12 to 1.25). Two trials using tablets in sectioned polythene bags as the intervention also noted an increase in participant-reported treatment adherence: the cluster-RCT (6 clusters) compared it with tablets in paper envelopes, and the other trial compared it with syrup in bottles (RR 2.15, 1.76 to 2.61; 299 participants). Authors' conclusions There is insufficient evidence to determine the effect of unit-dose packaged antimalarial drugs on treatment failure. Unit-dose packaging supported by prescriber training and patient information appears to improve participant-reported treatment adherence, but these data come from trials with methodological limitations.