Aristolochic acid A is an aristolochic acid that is phenanthrene-1-carboxylic acid that is substituted by a methylenedioxy group at the 3,4 positions, by a methoxy group at position 8, and by a nitro group at position 10. It is the most abundant of the aristolochic acids and is found in almost all Aristolochia (birthworts or pipevines) species. It has been tried in a number of treatments for inflammatory disorders, mainly in Chinese and folk medicine. Aristolochic acid A (Aristolochic acid I; TR 1736) is the main component of plant extracts Aristolochic acids, which are present in Aristolochia and Asarum herbaceous plants. Aristolochic acid A significantly reduces the activity of activator protein 1 (AP-1) and NF - κ B. Aristolochic acid A reduces the expression of bladder cancer related BLCAP gene in human cells.

Aristolochic acid B is an aristolochic acid that is phenanthrene-1-carboxylic acid substituted by a methylenedioxy group at the 3,4 positions and by a nitro group at position 10. It has a role as a metabolite, a mutagen, a carcinogenic agent and a nephrotoxin. It is a member of aristolochic acids, a monocarboxylic acid, an aromatic ether, a C-nitro compound, an organic heterotetracyclic compound and a cyclic acetal. Aristolochic acid B, one of the major components of the carcinogenic plant extract aristolochic acid, is known to be mutagenic and to form DNA adducts in vitro and in vivo, AAII shows more carcinogenic risk than aristolochic acid I, and this may be, at least partly, the result of its increased levels in kidney and plasma. Aristolochic acid B is an orally active major component of aristolochic acid (AA). Aristolochic acid B can be isolated from plants of the Aristolochia genus. Aristolochic acid B can form DNA adducts. Aristolochic acid B has mutagenicity. Aristolochic acid B exhibits a greater carcinogenic risk in vivo than Aristolochic acid I (HY-N0510).