Citronella oil is a yellowish oil derived from leaves and grass. It has a strong grassy, citrus, or floral scent, which helps to repel insects like mosquitoes that rely on their scent to locate people. That’s how citronella works: it’s not that mosquitoes detest the smell, but rather, it masks your smell so it’s harder to find you.
Citronella oil is also sometimes used as perfume, as a food additive, to promote wound healing, and even as an antifungal agent.
Mosquitoes use scent to locate people to feed on. A strong scent like citronella in the air makes it difficult for them to smell anything else.
Research has shown that citronella oil, when combined with vanillin, can provide mosquito protection for three hours. When combined with DEET, a citronella product can protect you for over six hours. However, citronella candles alone have mixed results. They may provide some initial benefit, but it will quickly wear off.