Why do plants need laxatives?
All plants contain chemical substances and, within plant chemistry, they are often divided into primary and secondary metabolites. The primary metabolites, e.g., various nutritional substances, vitamins or hormones, are of vital importance for the plant. Secondary metabolites are substances that are, generally speaking, not necessary for the survival of the plant, but which nevertheless increase the competitiveness of the organisms. The presence of such substances is of great interest for humans too, since they can often be used to make our lives easier.
It is rare that a plant itself has a need for a laxative, something to reduce blood pressure or to combat pain. But if a herbivore eats a plant which affects it negatively, it will possibly refrain from eating the same species again. If the plant tastes awful or give you diarrhoea after eating it, you don’t eat it again.
Man has learnt to use some of these substances for medicinal purposes. The next time you see a plant or an animal, just think that it is a little factory for producing chemical weapons that can cause all sorts of effects.