Tincture of benzoin is a pungent solution of benzoin resin in ethanol. A similar preparation called Friar's Balsam or Compound Benzoin Tincture contains, in addition, Cape aloes or Barbados aloes and storax resin. Friar's balsam was invented by Joshua Ward around 1760.
Compound Benzoin Tincture is often applied to skin under adhesive bandage. It protects the skin from allergy to the adhesive and makes the bandage adhere longer. It is also used by athletes for its reputation of toughening skin. Orthopedists often apply it under a cast, because it protects the skin and diminishes itching.
It can be applied to skin fissures, canker sores and fever blisters as a styptic and antiseptic. Tincture of Benzoin is still available in small quantities by 3M and co-branded with Steri-Strip skin closures. It is packaged in small clear glass ampules containing 0.6mL and plugged with a fluffed cotton bung. It is thought that light turns the Benzoin in these modern containers to a darker color. The newly produced tincture is often quite clear until mixed and heated in a pot of water or left uncapped or exposed for an unspecified time, at which it turns to a maple syrup brown color. It is unknown if oxidation occurs to produce the dark color or the effects of UV light on the substance. The compounding of Benzoin with other substances Aloe, Tolu balsam is also thought to cause the variation of color.
The Tincture of Benzoin is usually available under a number of brand names in 60 mL dark amber glass bottles. This is the traditional way of packaging as opposed to the individual applicators currently made popular by 3M in hospitals with Steri-Strips.
It is still issued and used in the U.S. military to treat blisters. A common treatment utilized by medics in the U.S. Army is to drain the fluid from a blister and then inject enough compound tincture of benzoin into the void to glue the blister to the underlying skin, to serve as a local antiseptic, and to prevent further abrasion or loss of skin. This is commonly known as a "hot shot" amongst military personnel due to the extreme burning sensation that will be experienced for several moments when the tincture is applied. Those who have undergone this treatment do not find the blisters to cause any irritation subsequently, causes for this could either be somatic or psychological as the medicinal properties have not been adequately studied.
Both compounds are also used in cosmetics.