balsam (bôlˈsəm) [key], fragrant resin obtained from various trees. The true balsams are semisolid and insoluble in water, but they are soluble in alcohol and partly so in hydrocarbons. They contain benzoic or cinnamic acid; these include Peru balsam and tolu balsam (both obtained from varieties of the South American tree Myroxylon balsamum of the pulse family), benzoin, and storax. Other resins called balsams include Mecca balsam (balm of Gilead), Canada balsam, and copaiba. Balsams are often used in medical preparations and perfumes.