Plants make natural poisons to protect themselves, and if we eat them, these can sometimes harm our bodies.

We’ve reviewed one assertion on whether plant toxins are harmful to humans when consumed, and it supports the idea that plants produce natural compounds to defend themselves, which can sometimes affect our bodies if we eat them [1]. What we’ve found so far is limited to this single point, with no studies or claims contradicting it. Plants make chemicals like alkaloids, lectins, and oxalates—not to harm us, but to deter animals and insects from eating them. Some of these compounds can interfere with digestion, trigger inflammation, or affect nutrient absorption in humans, especially when eaten in large amounts or raw. For example, solanine in green potatoes or cyanogenic glycosides in cassava can cause issues if not prepared properly. But these effects are not universal—they depend on the type of plant, how it’s cooked, how much is eaten, and individual biology. We don’t have enough evidence to say how common or serious these effects are for most people eating a normal diet. There’s no data here on whether these toxins cause long-term harm, or if the body typically handles them without issue. The one assertion we’ve seen doesn’t tell us how often harm occurs, or whether avoiding these compounds improves health. So far, the evidence we’ve reviewed suggests that some plant-made chemicals have the potential to affect human biology, but we can’t say how often this leads to actual harm in real-world eating patterns. In everyday terms: some plants contain natural chemicals that can be tricky for your body if you eat too much of them raw or unprepared—but that doesn’t mean you should avoid plants. Cooking, soaking, and balancing your diet usually reduces any risk.