The roots of two peony species, Paeonia lactiflora Pallas and Paeonia veitchii Lynch are routinely referred to as either chishao () or baishao (). This paper reviews the botanical origins and traditional medicinal usage of each species, as well as pharmacological like activity of their constituents. A search of herbal pharmacological encyclopaedia, PubChem and PubMed databases identified their known constituents. The biological data for these constituents were evaluated and classified according to pharmacological-like activity, with emphasis on compounds of greatest concentration and bioavailability. It was found that P. lactiflora and P. veitchii have some common compounds; however, their phytochemical bioavailability varies. Furthermore, a larger number of compounds have been identified in P. lactiflora. These have greater potential for antiinflammatory, antiviral, antibacterial and antioxidant therapeutic activity compared with P. veitchii. However, evidence indicates both species are similarly indicated for antiviral and glycaemic activity. Major compounds of each are classified as flavonoids, hydrolysable tannins (polyphenols) and monoterpene glycosides. The evidence suggests both species, when administered in entire botanical form, have an excellent safety profile; however, constituent toxicity risk evidence is limited, requiring further investigation. Although experiments show many compounds have biological activity, further investigation of their therapeutic potential is needed. Copyright © 2016 John Wiley & Sons, Ltd.