Usnea barbata is a lichen. It contains usnic acid, which is reported to have antimicrobial activity. Usnea barbata extract, usnic acid, and copper usnate have been used in topical preparations.

Adverse effects.

Two patients developed severe hepatotoxicity believed to be associated with usnic acid contained in a multi ingredient herbal preparation promoted for weight loss; one patient required emergency liver transplantation.¹

Ger.: Dr Grandel Granobil†; Tetesept Hals-activ; Ital.: Vidermina; Zeta N. Multi-ingredient: Indon.: Scabicid; Ital.: Foot Zeta; Micofoot; Steril Zeta.