Flavonoids, found in high amounts in calendula, are thought to account for much of its anti-inflammatory activity. Other potentially important constituents include the triterpene saponins and carotenoids.
Investigations into anticancer and antiviral actions of calendula are continuing. At this time, insufficient evidence exists to recommend the use of calendula for cancer. Nevertheless, test tube studies have found antiviral activity for calendula. The constituents responsible for these actions are not clear, however, and the relevance of these actions for human health care has not been established.