Carnosic acid is an abietane diterpenoid that is abieta-8,11,13-triene substituted by hydroxy groups at positions 11 and 12 and a carboxy group at position 20. It is isolated from rosemary (Rosmarinus officinalis) and common sage (Salvia officinalis) and exhibits anti-angiogenic, antineoplastic, antioxidant and anti-HIV activity. It has a role as an antineoplastic agent, an antioxidant, a HIV protease inhibitor, an angiogenesis modulating agent, an apoptosis inducer, a plant metabolite, an anti-inflammatory agent and a food preservative. It is an abietane diterpenoid, a carbotricyclic compound, a member of catechols and a monocarboxylic acid. It is a conjugate acid of a carnosate.