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Toxic Herbs that Should not be Ingested

Published: 2009-03-22 - Updated: 2013-06-14
Author: Dr Jenny Tylee
Peer-Reviewed Publication: N/A
Additional References: Herbalism and Herbs Publications

Synopsis: List of some herbs that are toxic and should not be taken internally without special care or professional supervision. I prefer to use herbal medications rather than pharmaceuticals, partly because herbs are gentler and safer.


Main Digest

I prefer to use herbal medications rather than pharmaceuticals, partly because herbs are gentler and safer.

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However I am not suggesting that herbs are harmless. Indeed some can be deadly. Listed below are some herbs that should not be taken internally without special care or professional supervision, though some are quite safe for external use (for example, arnica).

Many of the herbs that are listed here are used in controlled doses under the supervision of a herbalist. Some of these herbs will also appear in herbal formula. It is important to read labels and to be aware of the potential effects - beneficial and hazardous of any herb used.

The list below contains some of the potentially hazardous herbs however there are some precautions or special considerations that need to be given when using some herbs. Some will affect or interact with medical drugs such as the contraceptive pill. Others are also best avoided used during pregnancy and breast feeding.

Arnica (Arnica montana) - should not be taken internally (other than as a homeopathic preparation) as it is potentially toxic, but it provides one of the best remedies for external local healing of bruises and strains.

Belladonna (Atropa belladonna)

Bittersweet (Solanum dulcamara) - The stems of bittersweet is used in the treatment of skin and rheumatic complaints. Ointments can be made from the leaves and stems. However the berries have much higher levels of alkaloids and they may be poisonous and have to be avoided.

Bryony (Bryonia dioica)

Chaparral (Larrea tridentata)

Comfrey (Symphytum officinale) The roots are for external use only. The leaves can be taken internally but avoid excessive consumption. Care needs to be taken when applying externally to deep wounds as the external application of the leaves can lead to tissue forming over the wound before the wound has healed deeper down leading to the formation of a sinus.

European pennyroyal (Mentha pulegium)

False hellebore (Veratrum viride)

Foxglove (Digitalis purpurea) Digitalis is used in the treatment of heart problems it has the potential to be lethally toxic.

Henbane (Hyoscyamus niger)

Indian snakeroot (Rauwolfia serpentina)

Ipecac (Cephaelis ipecacuanha) - this is a very powerful herb and is an emetic - will induce vomiting and as such is used in the treatment of poisoning. It should be only used in very small amounts - if it is used at all.

Jimsonweed (Datura stamonium)

Lily of the valley (Convallaria majalis) this is a digitalis is the same as foxglove although without some of its toxic effects. Care still needs to be taken and is best used under the supervision of a health professional.

Male fern (Dryopteris filix-mas) - is effective in killing tapeworms. However, it is potentially poisonous in overdose and is best used under the supervision of a health professional.

Mandrake (Mandragora officinarum)

Mayapple (Podophyllum peltatum)

Mistletoe (Viscum album) - has a soothing and relaxing effect on the nervous system. However you need to avoid the berries as they can be poisonous.

Pasqueflower(Anemone pulsatilla) - this is an excellent relaxant herb but do not use the fresh plant.

Pennyroyal (Hedeoma pulegiodes) - is used for abdominal pains and flatulence but do not use during pregnancy as it has been used in large does and an abortifacient.

Pheasant's eye (Adonis vernalis)

Poke root (Phytolacca americana) - has a wide range of uses and is very powerful so it is used in 1/4 of the normal doses. Only use the poke root dried and in small doses. In large doses it will cause vomiting and diarrhea. Never use poke root in pregnancy. Poke root may be toxic if taken in large doses or for an extended period of time. It would be best not to take this herb unless under the supervision of a health professional.

Squill (Urginea maritima) - is used as a powerful expectorant in chronic bronchitis. However the does need is quite small so extra care is needed to prevent overdose.

Yellow jessamine(Gelsemium sempervirens)

Take care, not fright!

Other herbs also cause side effects, especially if they are taken in large doses and some herbs should only be taken when under the supervision of a herbal practitioner or other knowledgeable health professional. There is no need to be scared or too afraid to become more self-reliant. However, due care must be taken and sometimes professional advice, supervision or tuition is a worthwhile and sensible step in becoming self-reliant.

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Reference: Dr Jenny Tylee is an experienced health professional who is passionate about health and wellbeing. She believes that health is not just absence of disease and seeks to actively promote vitality and wellness through empowering others. She encourages people to improve their health by quit smoking, cleansing their body, taking essential vitamin and mineral supplements and many other methods, including herbal remedies. Visit Dr Jenny's blog at

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Cite This Page (APA): Dr Jenny Tylee. (2009, March 22). Toxic Herbs that Should not be Ingested. Disabled World. Retrieved December 2, 2022 from

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