Citronellal or rhodinal (C10H18O) is a monoterpenoid aldehyde, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent. Citronellal is a main isolate in distilled oils from the plants Cymbopogon (excepting C. citratus, culinary lemongrass), lemon-scented gum, and lemon-scented teatree. The (S)-(−)-enantiomer of citronellal makes up to 80% of the oil from kaffir lime leaves and is the compound responsible for its characteristic aroma. Citronellal has insect repellent properties, and research shows high repellent effectiveness against mosquitoes. Another research shows that citronellal has strong antifungal qualities.

Compendial status