Rhus integrefolia, commonly known as lemonade berry or lemonade sumac, is an evergreen shrub or small tree in the family Anacardiaceae. The genus name Rhus derives from Ancient Greek rhous, used for sumac plants, while integrefolia comes from Latin integer (“entire”) and folium (“leaf”), distinguishing it from other sumacs with serrated or compound foliage.

Rhus integrefolia is native to coastal southern California and northern Baja California, where it grows in chaparral, coastal scrub, and dry canyon habitats. Historically, the fruits were used by Indigenous peoples of the region, including the Chumash, Tongva (Gabrielino), and Kumeyaay, who soaked the sticky red drupes in water to create a mildly sweet–sour beverage similar to lemonade and also consumed the fruits fresh or dried. In modern contexts, the plant is mainly valued as a native ornamental and ecological species, though ethnobotanical interest in traditional beverages and wild foods has renewed attention to its culinary potential.

The primary ingredient derived from this food source is the fruit, particularly the outer acidic coating of the drupes used for beverages or flavoring infusions. The fruits contain organic acids that contribute to their sour taste, flavonoids such as quercetin derivatives with antioxidant activity, and tannins that provide astringency and mild antimicrobial properties. Unlike the closely related Rhus toxicodendron group, Rhus integrefolia does not contain high levels of urushiol in the edible fruit tissues, making it safe for traditional food use when properly prepared, although other parts of the plant may still cause irritation in sensitive individuals.