- Any of several plants, of the genus Hypericum, especially Hypericum perforatum, that have yellow flowers and traditionally ward off evil.
2013 March 1, David S. Senchina, “Athletics and Herbal Supplements”, American Scientist, volume 101, number 2, page 134:
- Athletes' use of herbal supplements has skyrocketed in the past two decades. At the top of the list of popular herbs are echinacea and ginseng, whereas garlic, St. John's wort, soybean, ephedra and others are also surging in popularity or have been historically prevalent.
- (uncountable) The plant prepared as a medication.
any plant of the genus Hypericum