The hypothesis that the ingestion of Allium sativum provides protection against bloodsucking pests such as mosquitoes was investigated in an RCT. Subjects were asked to consume either A. sativum (garlic) on one visit or a placebo on another visit. They were then exposed to laboratory-reared Aedes aegypti (Linnaeus) (Diptera: Culicidae). The number of mosquitoes that did not feed on the subjects, the number of mosquito bites, the weights of the mosquitoes after feeding and the amounts of blood ingested were determined. The data did not provide evidence of significant systemic mosquito repellence.