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Summer has arrived across many parts of the planet, with the bountiful cornucopia the warm season brings. You may be the recipient of a cornucopia of emails from various sites urging the use of herbs and mushrooms to boost your immunity, especially against a deadly novel virus. If one of your social distancing and nature fix activities is to get out and try to find your own wild medicinal or nutritious plant matter, refer to Part 1 (introduction to foraging) and Part 2 (medicinal plants and mushrooms) of this series “Free Food and Medicine.” To complete the series, Part 3 will discuss plant and mushroom toxicity.

Considering that there are over 400,000 plant species on earth and millions more of fungi, the annual number of poisonings from toxic exposures is comparatively low— around 50,000 annually in the US; the majority are nonlethal ingestions in curious children. Even those who are knowledgeable and experienced foragers and herbalists may occasionally misidentify or improperly prepare plants they have harvested for food or medicine and may experience serious toxicity, rarely including death. Wilderness hikers who want to spice up that backpack stir-fry may fall prey to misidentification. And seekers of that natural high from purportedly hallucinogenic plants and mushrooms may expand their consciousness to the eternal beyond if they make a fatal mistake in identification or imbibe a lethally high dose.

By now, most people in the wilderness medicine world should know that after published research about Chris McCandless, the protagonist of Jon Krakauer’s "Into the Wild", it is clear he did not die at the hands of the seeds of the wild potato, H. alpinum (but most likely starvation). However, the tragic story serves as a cautionary tale to those who ingest wild plants for sustenance that correct identification of a plant, including which parts of the plant are suitable for consumption, is vital.

Toxic exposures to any substance can occur by:

  • Ingestion
  • Irritant (topical, absorption)
  • Inhalation
  • Injection

With regard to plant and mushroom toxicity, the main route of exposure is ingestion. The second is irritant or topical—think poison ivy, oak, and sumac. Inhalational toxicity can occur if a plant is burned and the smoke enters the respiratory tract, such as poison ivy. Injection toxicity would be unusual unless a plant was prepared for this route (most likely for recreational use or if it is weaponized).

Green Deane from Eat the Weeds has developed the acronym ITEM for safe foraging to avoid accidental poisoning. Other tips are incorporated from Learn Your Land.

Identification – never eat a plant that you cannot positively identify when you first start to forage. Initially, don’t rely solely on photos – cross-reference using multiple identification sources, and check with a local expert who knows what plants look like in the area you are foraging.

Time of year – makes a big difference. A plant that is flowering in a different season than it is supposed to could be another plant that might potentially be toxic.

Environment – as discussed in the introduction to this series, make sure the soil or water the plant is growing in is not contaminated with toxic pollutants.

Method of preparation – most plants and pretty much all mushrooms are only toxic when ingested, ie, you can touch or smell them, unless they cause cutaneous reactions, discussed below, or you are unknowingly allergic. Many plants and all mushrooms need to be cooked or prepared in other ways before they are safe to eat. Initially eat only a small amount, and only one type of new plant/mushroom. Save a few pieces of the forage for identification in case you get sick later.

Herb and Plant Safety and Toxicity

An interesting classification of safety issues associated with medicinal herb use was proposed by Boon H and Smith M in: The Complete Natural Medicine Guide to the 50 Most Common Medicinal Herbs (Toronto, Ontario, Canada: Robert Rose Inc., 2004).

Safety Issues Associated with Medicinal Herb Use

  • Sins of Omission
    Patient self-medicating inappropriately and getting worse
  • Intrinsic Procedural Risks
    Allergic reaction

    Misidentification of plant
    Intentional/unintentional adulteration with heavy metals or pharmaceuticals, ie, foraging near road, contaminated water
    Suspected interactions with conventional medications
  • Situational amplifications
    Herbal therapy aggravates an existing condition (e.g., a detoxifying protocol)
    Use in pregnancy and other conditions--data often lacking
  • Worthless procedures
    When effective treatment exists but the natural product touted for its effect is useless

Serious Toxicity: Information for First Responders

A system for classifying herb and plant poisonings by toxidrome (toxic syndrome) and clinical symptoms has been recently suggested for more rapid and efficient diagnosis and treatment by first responders. This is in contrast to traditional plant poisoning classification schemes, which have been based on plant compound chemistry and pharmacologic effects. The table below presents this toxidromic classification system for a number of common herbs and plants which may result in fatal toxicity if ingested. Information about treatment appears also.

Adapted from: https://www.wemjournal.org/article/S1080-6032(15)00430-5/pdf
*In a case of mistaken identity, Death camas violently sickened members of the Lewis & Clark expedition who mistook it for the edible blue camas.
**The deadliest of them all.
***Don’t eat the cake-topper.
[see “Entertaining Read” reference at the end of this article]

General First Aid for Plant Poisonings

If a suspected plant poisoning has occurred, call the National Poison Center hotline:
1-800-222-1222. Refer to the following site for useful general information about plant ingestions: https://www.poison.org/articles/plant

As well, there are a number of plants that cause cutaneous reactions. Everyone knows the triple threat of Toxicodendron (poison ivy, oak, sumac). But others that can get under your skin include nettles, with their annoying urticating hairs, and the kitchen gardener’s bane, like carrots, parsnips, dill, fennel, celery and parsley, which can cause photosensitive reactions. More information can be found here: https://www.poison.org/articles/2011-jun/skin-problems-from-outdoor-plants

Common plants that are look-alikes with varying toxic effects include the following. Please consult a plant identification source for photos.

Mushroom Toxicity

As the old saw goes: There are old mushroom hunters, and there are bold mushroom hunters. There are no old, bold mushroom hunters.

Major mushroom toxins are presented in the table below. As with plants, call the National Poison Center hotline for possible toxic mushroom exposures. And consult this site for useful information: https://www.poison.org/search-results?q=mushroom&page=1

Adapted from: https://www.foragingwildmushrooms.com

Entertaining Read on Poisonous Plants During Quarantine

While you are waiting for the all clear to resume normal activities, this is an eminently entertaining and educational read on poisonous plants. And there’s a coloring book available too!

Amy Stewart. Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities. Chapel Hill, NC, Algonquin Books: 2009.

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