Mixing herbal remedies and conventional drugs 'could be harmful'

Alternative treatments could alter effects of prescription medication, warn researchers

Herbal remedies such as St John's wort, ginseng and ginkgo biloba could have harmful interactions with conventional drugs, scientists have warned.

In an extensive review of the medical literature, the team uncovered dozens of cases in which alternative treatments appeared to have altered the effects of prescription medication, either diluting it, making it more potent or causing potentially dangerous side effects.