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Today is different from the past.
Back when Chen Zhou was surviving on a deserted island, he made quite a few mistakes due to unfamiliarity with marine products and plants, even mistaking a non-toxic shrimp for a deadly one, going 28 years on the island without daring to eat it.
After returning to the modern era and getting involved in extreme sports, meeting many wilderness survival enthusiasts, he managed to cram some knowledge in this area.
For example, he can identify two common toxins found in plants, such as hydrogen cyanide and oxalic acid.
Hydrogen cyanide has a smell similar to bitter almonds, and an average person can smell it by breaking a leaf open; for him, identifying it by scent is no problem at all.
Toxic substances like sodium oxalate and wild rhubarb exist in leaves or chestnut trees.
When a cut leaf stalk's sap contacts the skin and feels dry or burning, it indicates the presence of oxalates, which he can also identify.
