While there is no substitute for learning and correctly identifying edible wild plants, if you were to find yourself stuck in a survival situation miles from civilisation with little or no knowledge of what you could eat, then your options might seem limited. With few exeptions all animals are edible, but apart from insects and grubs, are generally more difficult to find and catch. Plants on the other hand are usually abundant in most regions of the world. The problem however is that the majority of wild plants are toxic for us, therefore it becomes essential to determine their edibility before you can eat them. The following new Edibility Test was developed by the United States Air Force (USAF). Also known as the Rule of Eight, this test has been extensively tested and revised over time, and addresses many of the shortcomings and failings of the previous Universal Edibility Test (which is highly recommended you DO NOT use).

It has been designed as a catch-all test. As such it can give some false positive results, for example dandelion which is edible, has milky sap and therefore would fail this test. Likewise, a few edible plants that have umbrella shaped flowers would also fail this test.

At the time of writing this, and to the best of our knowledge, there are no known toxic or poisonous plants that would slip through this test provided you follow these instructs EXACTLY. Pay particular attention to the section on plant selection as there are a number of dangerous plants that would pass the smell, skin, and taste tests, but that if you were to ingest would make you ill and could even be fatal.

IMPORTANT: This test should ONLY be used as a last resort. It should not be used as a substitute for learning and identifying those wild plants that are edible and those that are not.

  • Start with an 8-hour empty stomach.
  • Test only one plant part at a time.
  • Drink only purified water during the test if possible.
Plant Selection
  • Test only plants available in sufficient supply.
  • Test leaves and stems from plants growing in shade or in moist soil.
  • Test high energy starchy parts of the plant, like seeds, roots, stalks and bulbs.
  • Test black, blue and red berries.
  • Never test white, green or yellowish berries.
  • Never test fungi (i.e. mushrooms, mold).
  • Never test seeds in pods (i.e. beans, peas).
  • Never test plants with umbrella shaped flowers.
  • Never test plants with milky sap (i.e. poinsettia, poison oak).
  • Never test shiny/glossy leaf plants.
  • Never test plants beside major roads and railways.
Smell Test
  • If any unpleasant odor is present - FAILS TEST - DON'T EAT.
  • Moldy or musty - FAILS TEST - DON'T EAT.
  • Unusual smell - FAILS TEST - DON'T EAT.
  • Almond scent - FAILS TEST - DON'T EAT.
Skin Test
  • Place juice from plant part on out lip for 8-minutes.
  • If reaction occurs - FAILS TEST - DON'T EAT.
  • If no reaction occurs, move on to taste test...
Taste Test
  • Taste a small amount of the juice from the plant part.
  • If unpleasant taste - FAILS TEST - DON'T EAT.
  • Chew a pinch of the plant part and leave in mouth for 8-minutes.
  • If unpleasant taste or reaction - FAILS TEST - DON'T EAT.
  • If no reaction occurs - swallow.
Digestion Test
  • After swallowing, wait 8-hours.
  • If no reaction occurs, then...
  • Chew a handful of the plant part, swallow, and wait another 8-hours.
  • If no reaction occurs...