53] Cancer Research UK caution that there is no reliable evidence for the effectiveness of herbal remedies for cancer.[
Plant medicines have often not been tested systematically, but have come into use informally over the centuries. By 2007, clinical trials had demonstrated potentially useful activity in nearly 16% of herbal extracts; there was limited in vitro or in vivo evidence for roughly half the extracts; there was only phytochemical evidence for around 20%; 0.5% were allergenic or toxic; and some 12% had basically never been studied scientifically.[53] Cancer Research UK caution that there is no reliable evidence for the effectiveness of herbal remedies for cancer.[102]