Some people believe that all herbal products are safe. This is far from true. Although this is not a complete list of unsafe plants, those mentioned deserve special attention.

The following herbs are dangerous and should not be used as remedies. [...without a great deal of study, training, and introspection. -Ed.]

  • BORAGE: Harmful in large doses; may cause liver damage and cancer
  • BROOM: Toxic; diuretic
  • CHAPARRAL: May cause illness; banned in the United States
  • COLTSFOOT: May cause cancer
  • COMFREY: May cause liver damage and cancer (but not through external use)
  • FOXGLOVE: Potent heart toxin
  • PENNYROYAL: The essential oil may cause convulsions in large doses; possibly harmful to pregnant women.
  • POKEWEED: May cause respiratory paralysis and convulsions
  • RUE: May cause skin to more susceptible to damage when exposed to sunlight
  • SASSAFRAS: May cause cancer

The following herbs are potentially dangerous and should be used with caution.

  • ALOE VERA: The juice can be a powerful laxative when used internally (gels labeled for internal use do not have this effect)
  • EPHEDRA: Should not be used by people with heart conditions, high blood pressure, diabetes, or thyroid disease
  • JUNIPER: Should not be used by women who are pregnant or by people with kidney disease
  • LICORICE: Excessive amounts may cause fluid retention and high blood pressure
  • YOHIMBE: Side effects include nausea, vomiting, high blood pressure, palpitations, insomnia, and tremors

SOURCE: DRUG-FREE HEALING: Breakthrough Remedies for Healing Yourself Naturally, by the editors of PREVENTION Magazine Health Books