Will hemp essential oil be in your pet's next flea treatment? Doesn't do much on adult fleas, but it appears to be very effective at low doses for killing the flea eggs and larvae. A couple of the terpenes in cannabis are responsible for the insecticidal effect. The link leads to the full study. Insecticidal activity of essential oil of Cannabis sativa against the immature and adult stages of Ctenocephalides felis felis. (Brazil) (full – 2023) Insecticidal activity of essential oil of <i>Cannabis sativa</i> against the immature and adult stages of <i>Ctenocephalides felis felis</i> Essential oil (EO) of Cannabis sativa (C. sativa) was evaluated against the egg, larval, pupal, and adult stages of the flea Ctenocephalides felis felis. The chemical composition of EO was determined by gas chromatography with flame ionization and mass spectrometry. EO mainly comprised γ-elemene (16.2%) and caryophyllene oxide (14.2%) as major compounds. To evaluate the mortality of flea stages in vitro, filter paper tests were performed at different concentrations. EO of C. sativa showed insecticidal activity (100% mortality at the highest concentrations) for flea control at egg, larval, pupal, and adult stages, with lethal concentrations (LC50) of 32.45; 91.61; 466.41 and 927.92 μg/cm2, respectively. EO of C. sativa indicated the potential for the development of ectoparasiticide for veterinary use, especially for fleas in egg and larval stages. Granny