Covering: 1990–2005. Previous review: Nat. Prod. Rep., 2005, 22, 487 This article reviews the pharmacological activity of naturally occurring triterpenoids excluding the degraded triterpenoids and cucurbitacins which have been reviewed recently. The therapeutic activities discussed include anticancer, anti-inflammatory, antiulcerogenic, antimicrobial and antiviral activity. 227 references are cited.