Citrus aurantifolia, also known as key lime, is a shrubby tree that produces a green, spherical fruit. Lime fruit has a high acidity and a strong aroma. Lime oil is often added to skin care products as a fragrance ingredient because it contains the fragrance chemicals bergapten and limonene.

Despite its pleasant scent, it is often recommended to avoid skin care products that contain lime oil because this ingredient can sometimes cause phytophotodermatitis upon contact with the skin. Phytophotodermatitis is a chemical reaction that makes the skin extra sensitive to ultraviolet light, resulting in a patchy, uneven appearance to skin. Experts believe that its sensitizer potential outweighs any benefits.