Most healthy poisons in the world
The main goal of any lifeform is to survive and take over the world. In childhood most of us thought about why oranges and apples are so tasty? Why do plants create such delicious fruits? Do they want us to eat them? In reality though, plants are simply making nutritious fruits, and our evolution made us believe that nutritious food is delicious. No plant is interested in having its fruits eaten, except of course this is the way to spread its seed further away from itself. On the contrary, plants have developed different toxins and poisons to prevent animals from eating them. Many animals have learned to deal with and digest those toxins. For example, koalas are practically only animals capable of digesting incredibly toxic eucalyptus leaves. Such an unusual diet left them with no herbivorous rivals and made their meat practically unsuitable for food, which is why most predators avoid them.
Unlike koalas, humans have not developed such abilities, however, thanks to our ingenuity and ability to use various natural gifts for our own good, we have learned to use many poisons from plants and animals as medicines. In fact, almost any medicine can be called poison, and vice versa, it's all about the dosage. So poisons of plant origin that are used in medicine:
The ergot fungus usually parasitizes rye and wheat as well as other grains. It contains many different alkaloids that are toxic to humans. The main effect on the human body is muscle contraction (especially smooth muscles), various neurological symptoms and hallucinations. In high doses, due to prolonged contraction of smooth muscles, overall blood supply is disrupted and gangrene of the extremities develops. In small quantities, it is successfully used in gynecology to contract the uterus, as an aid during childbirth or to stop uterine bleeding. The ergot fungus was also used by Albert Hofmann to synthesize LSD.
The nightshade family includes such plants as belladonna, mandrake, datura, etc. All of them are poisonous. Atropine, widely known in pharmacology and medicine, is obtained from these plants. When ingested, atropine reduces the secretion of the salivary and gastric glands and lowers the tone of smooth muscle organs, which allows it to be successfully used in diseases of the gastrointestinal tract. The ability to reduce the secretion of sweat glands has been successfully used to combat excessive sweating, and its ability to increase the heart rate is also used to treat certain medical conditions.
Digitalis or foxgloves
Digitalis is the name of a plant genus that can contain cardiac and steroid glycosides, which are very toxic to humans and animals and can cause heart attacks and in some cases even heart failure. Because of the way the toxins from these plants affect the heart, they are used in the manufacture of a drug called digitalin, which is used to control heart rate.
While plants do their best to scare away those who want to eat them by producing all sorts of complex poisons and toxins, ironically, some of them are now used by humans only because of those very poisons.