OBJECTIVES: Thai Herbs are a fascinating and viable natural alternative to conventional chemical mosquito repellents and larvicides. This study aims to analyze available data on the efficacy and safety of Thai herbs for mosquito repellents and larvicides.

METHODS: A systematic review and meta-analysis of clinical trials was conducted to evaluate the efficacy and safety of Thai herbs used as mosquito repellents and larvicides. MEDLINE, EMBASE, the Cochrane Controlled Trials Register were searched for relevant articles based on pre-defined inclusion criteria. Two reviewers independently extracted data from the selected articles. Data on efficacy and safety outcomes were collected. We calculated pooled mean protection time (mosquito repellent) and mean 50% lethal dose or concentration values; LD50 /LC50 (larvicidal), weighted mean difference and 95% confidence interval were reported.

RESULTS: A total of 33 studies were included in this analysis. Overall analysis indicated that extracts from the herbs analyzed had significant activity both as repellents as well as larvicides. Among agents conferring protection against Anopheles dirus, the longest protection time was seen with C.longa (480 minutes) even in comparison to the market standard chemical repellent, N, N-Diethyl-meta-toluamide; DEET (360 minutes), and 15%DEET lotion (120 minutes). The larvicidal effect of herbs as measured by LD50 (except, C.Aurantifolia and Z.limonella) were 83.92, 800.33, and 40.169 mg/l, respectively.

CONCLUSIONS:

Extracts of all Thai herbs showed various larvicidal and repellent activities. C.longa showed the highest repellent activity against mosquitoes. All 5 of the Thai herbs (A.graveolens, C.aurantifolia, C.longa, O.basilicum, Z.limonella) showed larvicidal activity (LD50) superior to DEET.