Spurred by California law, some manufacturers are adopting warning labels. A member of the mint family, it induces abortion. The FDA knows of one woman who died of cardiac arrest in 1994 while attempting a pennyroyal abortion. Once a flavoring for root beer, the oil is banned as a U.S. food additive. Eating lots of licorice root, a popular herb also found in some licorice candies, speeds potentially serious potassium loss when used with laxatives.
Flax seed can delay absorption of medicines.
Kava kava can increase the effects of alcohol and certain psychological drugs. High doses of Vitamin E cause bleeding in people taking blood thinners. So can bromelain, a pineapple enzyme used as a digestive aid. Also, doses of 25,000 International Units a day can cause severe liver injury, headaches and joint pain. Consuming for several months doses 10 times the daily recommended allotment of 10 micrograms can cause dangerously high calcium levels and lead to kidney damage.