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Wild Edible Plant Foraging Hazards and Tips

Tim Boyer's picture
Edible Plant

The odds are that if you are not a plant biologist or at least a fairly knowledgeable amateur botanist who is into foraging for wild edible plants, you may become one of a growing number of people who fall victim to accidental self-poisoning.

In the United States there are over 700 species of poisonous plants, many of which are nearly identical to some edible plant species. Edible plants are sought after by amateur foragers who enjoy the hobby of learning how to “live off the land” by engaging in primitive skills involving medicinal plants and herbs found in local parks, roadways and outlying areas.

“Foraging as part of a lifestyle is not really new,” says mycologist Karen Snetselaar, Ph.D., professor and chair of biology at St. Joseph’s University. “Guidebooks for food foragers have been around for years, as well as publications like Mother Earth News.”

In fact, foraging as a way of life predates many adaptive strategies such as horticulture, pastoralism, agriculture and industrialism by earlier societies as a means for survival. Foraging is a pre-farming economy with a foundation built on skills involving scavenging, hunting and gathering. Scientists point out that although such societies were typically disparaged as being primitive and brutal, foraging required very little time and thereby allowed ample opportunity for more cultured pursuits such as art, community activities and general enjoyment of the natural world.

Today, people from all walks of life are likewise embracing nature by rediscovering the ancient roots of foraging and gathering plants that can not only be used for medicinal purposes, but also in discovering new herbs to use in salads and other dishes. However, enjoyment can quickly turn to discomfort or even death if the wrong plant or wrong part of a plant is eaten.

“People new to foraging have to be very careful. There are many plants and fungi that are poisonous or have parts that are poisonous,” says Dr. Snetselaar. “Wild parsley looks a lot like poison hemlock, for example. The growing environment is also a factor, because plants will sequester toxins that are introduced to the soil or fall on their leaves, like pesticides.”

As it turns out there is more to identifying whether a plant is poisonous or not by simply comparing plants to images in guides or printouts from the Internet. Many sources that state a plant is safe fail to point out that some parts of a particular plant are toxic while other parts are safe to eat. For example, the bulb of the hyacinth and daffodil are toxic, but the flowers are not; while on the other hand, the flowers of the jasmine plant are the poisonous part of the plant.

Furthermore, this extends to many plants that are commonly used as food. One example is the fleshy stem (tuber) of the potato plant that is nutritious, while its roots, sprouts and vines are poisonous. In addition, the leaves of tomatoes are also poisonous, while the fruit is not. And remember those Rhubarb pies your grandmother made way-back-when with wild Rhubarb that grew on the family farm? As it turns out, while the stalks are good to eat—the leaves are poisonous.

Symptoms of plant poisoning range from irritation of the skin or mucous membranes of the mouth to nausea, severe stomach cramps, vomiting, convulsions, irregular heartbeat and sometimes death. Typically, the diagnosis of plant poisoning is often missed until it is too late because there are no tell-tale empty containers and no unusual lesions or odors around the mouth or other indications that a poisonous plant was ingested.

An example of one plant found to have been the source of an accidental self-poisoning by someone who was foraging for edible plants was traced to a species of plant called “Colchicum autumnale.” Plants within the Colchicum family are sometimes mistaken by foragers for similar-appearing Ramsons—also known as wild garlic—that are a wild relative of chive plants and sought after for their pungent aroma and taste used in pesto sauce in place of basil.

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Colchicum autumnale contains a chemical called colchicine that is known to stop cell division and is under investigation for its use as an anti-cancer drug. However, colchicine ingested directly from a plant presents symptoms similar to that of arsenic poisoning and there is no antidote to counter its lethal effects.

Two cases of plant poisoning with Colchicum autumnale resulted in identical symptoms with one patient suffering only moderate gastroenteritis and liver injury, whereas the other died of rapid and progressive multiple organ failure 52 hours after ingesting the plant.

Another hazard of foraging for edible plants is that while the plant may be identified correctly as safe to eat, the environment it grew in may prove to be toxic. Water run-off from nearby areas where fertilizers, herbicides, pesticides, or other harmful chemicals were used could be absorbed through a plant’s root system and sequestered within parts of the plants. Phytoremediation to remove contaminants in soil using plants grown over old landfills or other contaminated areas could hide hidden toxins in the soil of an otherwise pristine appearing landscape.

To protect yourself from accidental poisoning while foraging for edible plants, Dr. Snetselaar offers these four tips for novice foragers:

1. Educate yourself— Photo guides and iPhone apps do not sufficiently show plants and their parts for those unfamiliar with vegetation to distinguish the subtle differences that prove a plant edible or poisonous. Instead, learn the terminology associated with classification and rely on a more academic guidebook that has diagrams and shows a plant’s relative size.

2. Learn from an expert—Taking a seasoned forager as a guide is a safer and more informative way to learn what to pick.

3. Forage in untainted environments—Though people have been known to forage in urban settings, be wary of vacant lots and roadsides, where unknown pollutants can lie both underneath the soil and on vegetation itself. Do not forage where fertilizers and weed killers have been used and always wash plants before eating.

4. Check ordinances in parks and protected lands— Many state and national parks do not allow visitors to disturb protected environments by removing plant life and endangering regrowth.

Image Source: Courtesy of Wikipedia


”Colchicine poisoning by accidental ingestion of meadow saffron (Colchicum autumnale): pathological and medicolegal aspects” Forensic Science International 1999 Dec 20; 106(3):191-200; Klintschar M, Beham-Schmidt C, Radner H, Henning G, and Roll P.

St. Joseph’s University news “Eating Wild: Foraging Safely in a Modern World”



Good points, however, I would add that it is important to learn to identify the poisonous plants that are "look alikes" for the edible ones. I've found the Peterson Field Guides for Edible Wild Plants to be very helpful, showing the edible and poisonous ones side by side for comparison. I would also advise extreme caution when foraging mushrooms. I like to say that identifying a mushroom by its shape and color is like identifying a plant by its flower alone, not very reliable. And given the toxins in some wild mushrooms, I stick to the grocery store varieties.
The risk of foraging for wild mushrooms is especially poignant. I read about one case where someone decided to test their survival skills by eating a turtle caught in the wild, only to wind up poisoning himself not realizing that some turtle species consume posionous mushrooms as part of their diet.
Love that there is an iPhone app to help with this. Also, field guides are so useful. I have several pocket guides that I use to identify plants, insects and birds. I love them.