The investigations revealed that when the early fourth instars of Ae. aegypti were exposed to peppermint oil for 24 h, the LC50 and LC90 values obtained were 111.9 and 295.18 ppm, respectively. The essential oil was proved to be 11.8 % more effective when the exposure of the larvae to essential oil continued for 48 h, exhibiting an LC50 value of 98.66 ppm. The results obtained proved and established the efficacy of the M. piperita essential oil against the dengue vector larvae. All the treatments resulted in complete mortality of larvae without any pupal or adult emergence. The control or untreated groups did not show any mortality within 48 h. The larvae developed into pupae and then adults within 60-72 h. The essential oil of M. piperita has exerted promising and remarkable repellent activity against Ae. aegypti adults. The present studies revealed the percentage protection in relation to time (min). Our investigations resulted in 150 min of complete protection time with 0.1 mL of oil applied on the arms of human volunteers. After 150 min, the efficacy of oil decreased a little resulting in non-repellency of 7% of mosquitoes. Consequently, the % protection decreased to 27% in half an hour. First bite of the dengue vector was observed after 165 min of oil application, making the % repellency and protection of 96% and 88.8%, which decreased to be 93.2% and 73.1%, respectively after 180 min. The control treatment did not provide any protection even during the first trial. The number of bites in control treatment ranged only from