Citronella is a natural oil extracted from the leaves and stems of certain species of lemongrass. It is commonly used as an insect repellent, particularly against mosquitoes. The oil has a strong, lemony scent that many people find pleasant, making it a popular choice for outdoor candles and sprays. In addition to its repellent properties, citronella is also used in aromatherapy and as a flavoring in food and beverages. It is considered safe for most people when used appropriately, but some may experience skin irritation if applied directly without dilution.