This is a last-resort survival procedure, not a quick way to identify food. It takes many hours per plant and carries real risk if skipped or rushed. Read the caveats before the steps.
Hard rule: never apply this test to mushrooms or fungi. Mushroom toxins are frequently not neutralized by any of the steps below, can still be fatal in small amounts, and symptoms are often delayed until organ damage has already occurred. If you can't positively identify a mushroom from expert knowledge, don't eat it — full stop.
For plants only, once you've confirmed abundance (no point risking a plant you'll only find once):
- Separate the plant into parts (leaves, stem, root) — test one part at a time.
- Smell it. A strong, unpleasant almond or peach-pit smell is a red flag for cyanide compounds — discard.
- Contact test: rub a piece on your inner wrist or elbow, wait 15 minutes. Any burning, itching, or rash means stop.
- If no reaction, hold a small piece to your lips for 3 minutes, checking for burning or numbness.
- If clear, place on your tongue for 15 minutes without swallowing, checking for any reaction.
- If clear, chew a small piece and hold it in your mouth for 15 minutes, still not swallowing.
- If clear, swallow a small amount and wait 8 hours without eating anything else, watching for nausea, cramping, or discomfort.
- Only after a full 8-hour wait with no symptoms should you eat a modest amount of that plant part — and even then, keep monitoring.
This process must be repeated separately for every part of every plant. It is designed for genuine last-resort survival scenarios, not routine foraging — the time cost and risk are the point.