What is the Universal Edibility Test?
A skill taught in the United States Army Survival Manual, the universal edibility test is a technique for systematically assessing various parts of an unknown plant to determine if it is edible. It’s a skill that can be useful in dire emergency situations but is one that requires great caution and experience.
I was raised in a rural area and eating wild plants was a natural progression in my journey to adulthood. Popping a few berries and tasty leaves is a regular part of my hiking adventures, but it’s never something I do without caution. A single misidentification can have fatal consequences, or at least give you a case of diarrhea you do not want to have.
Why Eat Wild Plants?
The reasoning for eating wild plants is multifaceted.
If you’re on a hike and looking to capitalize on whatever resources are around you, edible plants can supplement your diet (hello, ultra lightweight hikers). Fresh, sun warm berries are incredibly delicious, and a few pieces of the aforementioned wood sorrel can add a bright and tangy taste to your campsite cooking.
But before you start sampling the greenery…
Heed My Warning!
Eating wild plants is never a light-hearted and flippant decision to make. Even a few bites of the wrong plants can be fatal or incapacitating. Many plants have mimics that are almost impossible to distinguish between each other.
“Mushrooms are not plants! Do not use the universal edibility test on mushrooms!”
Positive identification is absolutely necessary before you start chomping on plants for sustenance. DO NOT experiment with the universal edibility test casually, and ALWAYS err on the side of caution.
It can take a fit adult almost 30 days to starve to death. If you’re a few days out from rescue, hold off on eating wild plants until it becomes a do-or-die scenario.
Also, understand that mushrooms are not plants and therefore are not suitable for the universal edibility test.
Even with proper identification, individual parts of a plant can be fatally toxic (like the case of Christopher McCandless of Into the Wild fame).
Please refer to this guide (PDF warning) to understand how dangerous toxic wild plants can be.
The Universal Edibility Test
Follow these steps to determine if the plant in question is edible. Remember a cardinal rule of the universal edibility test, Test Only One Part of a Plant At a Time.
You should also test the plant parts as you intend to prepare them (raw, boiled, fried, etc).
Divide the Plant Into Leaves, Stems, Roots, Buds, and Flowers
The basic structures of a plant should be divided up. In general, if the plant produces a milky sap it should be avoided. You should smell the plant for strong odors; if they are present, discard the plant and do not consume it.
Try to abstain from eating for 8 hours before starting the universal edibility test to ensure your system is reacting to the plant in question. In this 8 hour period place a leaf or stem on the inside of your elbow to test for contact poisoning. If there is no effect after about fifteen minutes, you’re probably in the clear.
Only drink clean water while testing the plant parts.
Rub a Small Portion of the Plant Part on Your Lip
This is an important step to take. Many toxic plants will not cause a skin reaction to your interior elbow but will cause your lips to swell and tingle.
If there is the slightest sign of discomfort after touching the plant part to your lip, discard the plant part entirely. You’ll only need to wait about 5 minutes to know if it’s bothering you.
Place the Plant Part on Your Tongue
Hold the plant part on your tongue for 15 minutes. Discard immediately if it produces an uncomfortable feeling (tingling, numbness, burning). If there is no reaction to this test, move onto the next step.
Chew a Piece of the Plant Part
Chomp down and chew on the plant part and then hold it in your mouth for about 15 minutes but do not swallow it until 15 minutes have passed.
Wait 8 Hours
I know, I know; the waiting is the hardest part, but stand true and wait 8 hours after chewing the plant. If you start to feel any sort of ill effect during the period make yourself vomit and drink plenty of water. Discard the remaining portions of the plant.
Prepare More of the Plant Parts
No ill effects? Great! But before you jump too far into things, cool your jets and prepare ¼ cup of the plant as you intend to prepare it for consumption.
Ingest it, and if you feel no ill effects after 8 hours, the plant is probably safe to eat and has passed the universal edibility test.
The best way to identify what plants are edible is to learn about them before chowing down using the universal edibility test.
A few hours of reading, study, and in-depth research can provide you with a list of plants you can positively identify in the field. It’s a heckuva lot safer to know what you’re looking at that experiment with what’s going to happen after you eat it.
Learning about plants adds an entirely new facet of appreciation and understanding of the places you’re spending time outdoors. Those funky grasses are actually horsetails, and that crazy-looking flower that is shaped like a spaceship is a columbine.
In the eternally wise words of G.I. Joe, “Knowing is half the battle”. Possessing an educated understanding of the plants in your environment can eliminate the need for the universal edibility test.
But for those times when you’re in an unknown area and have nothing familiar to rely on, a strong grasp on the basic rules and guidelines of the universal edibility test can be a lifesaver.
- Foraging for Wild Edible Foods by James Kavanagh – An easily referenced guide to edible plants can readily fit into your pocket.
- Book of Forest & Thicket, The: Trees, Shrubs, and Wildflowers of Eastern North America by John Eastman – My go-to guide for anything Forest and Thicket, this guide provides ample resources on some of the most commonly encountered plants in Eastern North America.
- The Foragers Harvest by Samuel Thayer – It’s difficult to find a guide that can be reliable across a huge geographic area, but this one comes close. You’re better off with a regional foraging book, but this one is pretty handy for finding something you’ll encounter in the field.