Cilantro (Coriandrum sativum) is a popular herb in many cuisines, but it has also gained a reputation in folklore as a natural guard against biting insects. This common belief suggests that the plant’s strong, distinctive aroma may be enough to deter mosquitoes. As people seek alternatives to synthetic chemical repellents, the question of whether this simple kitchen herb truly offers protection has moved from folk wisdom to scientific investigation. The pleasant, fresh scent of the herb to humans often translates to something far more disruptive to a mosquito’s sensitive sensory system. This article explores the scientific backing behind the claim that cilantro can indeed repel mosquitoes.
The Scientific Evidence Behind the Claim
Scientific studies have generally focused on the essential oil extracted from the plant’s seeds, known as coriander oil, rather than the fresh leaves typically called cilantro. Laboratory testing has demonstrated that this essential oil possesses significant repellent activity against several mosquito species. One study found that coriander essential oil provided a median complete-protection time of 180 minutes against the Aedes aegypti mosquito, a carrier of yellow fever and dengue. This level of protection places cilantro essential oil among the more effective natural oils tested. Another investigation confirmed that the essential oil was a good repellent against the Asian tiger mosquito, Aedes albopictus, offering complete protection for over 60 minutes at higher concentrations. These results indicate that cilantro’s concentrated compounds disrupt mosquito activity, though this duration is generally shorter than that provided by synthetic gold-standard repellents. The effectiveness is highly dependent on the concentration and the specific mosquito type.
Chemical Compounds Responsible for Repellency
The documented anti-mosquito activity of cilantro essential oil is primarily attributed to Linalool, a specific volatile organic compound. Linalool is a naturally occurring monoterpene alcohol that constitutes a large percentage of the essential oil, often ranging from 60 to over 80%. Linalool works by interfering with the mosquito’s olfactory receptors, which are the sensory organs used to detect the carbon dioxide and specific body odors that mosquitoes use to locate a host. The strong, unfamiliar scent effectively jams the insect’s detection system, making it difficult for the mosquito to find a human target. The essential oil also contains smaller amounts of other volatile compounds, such as geraniol, which contribute to the overall repellent effect. These compounds evaporate rapidly, which is the main reason plant-based repellents require more frequent reapplication than synthetic products.
How to Use Cilantro as a Mosquito Repellent
For practical use, the most effective method is utilizing the concentrated essential oil rather than relying on the fresh herb alone. The essential oil, derived from the seeds (coriander), must be diluted with a carrier oil, such as coconut or olive oil, before being applied directly to the skin. A typical concentration for a topical repellent mixture is around 10% essential oil. Crushing fresh cilantro leaves and rubbing them directly on the skin is a traditional method, but the concentration of Linalool released is low, and protection will be minimal and short-lived. This method also carries a risk of skin sensitivity or irritation, a factor to consider when applying any plant matter directly to the skin. Positioning potted cilantro plants around a patio offers little to no effective protection because the volatile compounds are not released in high enough concentrations to repel mosquitoes over any significant distance.
Scientifically Backed Natural Repellent Alternatives
Since cilantro’s protection time is limited, individuals seeking effective natural alternatives have several options supported by strong scientific evidence. The most notable alternative is Oil of Lemon Eucalyptus (OLE), which contains the active compound para-menthane-3,8-diol (PMD). OLE is recognized by health organizations and can provide over 95% protection for up to three hours when used in a 30-32% concentration. Another highly effective option is catnip oil. Studies have shown catnip oil to be up to 10 times more effective than DEET, providing protection for two to three hours. Catnip oil’s activity comes from the compound nepetalactone, which is a potent mosquito deterrent. Citronella oil is also a common natural repellent, offering protection for up to two hours when formulated correctly, but its quick evaporation limits its duration of effect.