Can anyone say, deadly nightshade? Atropa belladonna is one of the deadliest plants in the world, with the ability to easily kill a fully grown adult human. All it takes in most cases is for someone to eat about 5 of the sweet berries of this plant and they will succumb to a lethal delirium. Vivid nightmarish hallucinations set in after consumption, causing the person to become dissociated from their own body and the world around them. It's not long until they're completely incapacitated and help is likely too late.
It's not all doom and gloom with deadly nightshade however. In fact, the atropine which is extracted from the plant is an extremely useful prescription drug when used in much lower, controlled doses. Not only can atropine be used to prevent heart failure, but it can calm stomach spasms, prevent vertigo and motion sickness, and even be used as an antidote for nerve gas poisoning. It's even present in a lot of over the counter cold medicines where it helps to reduce congestion and pain.
All of this makes atropine one of the most useful medical drugs, and it is even on the WHO's list of essential medicines. One of the world's most dangerous poisons, paradoxically, is one of the world's most beneficial and important medicines. It's all a matter of dosage.
Morphine is the gold standard of analgesic drugs. As a painkiller, it is used in hospital settings during operations and for the treatment of severely painful injuries and conditions. It is also used widely to alleviate the pain of dying when someone is terminally ill, allowing them to feel significantly more comfortable in their final hours.
Although it is one of the most powerful prescription drugs, it is also entirely natural. The opium poppy, papaver somniferum, contains several different alkaloids, the most concentrated and potent of which is morphine at roughly ten percent volume. These alkaloids are present in the form of opium, which is derived from the seed capsule of the flower.
To this very day, morphine can't be produced synthetically. It must be extracted from poppies that are grown specifically to produce the world's morphine supply. Countries like Tasmania grow much of this morphine supply, and it is fairly common for the farmers to notice native animals infiltrating their crop and eating the narcotic plant for its intoxicating high. Wallabies eat the poppy plant and hop around in circles, dazed and high, before leaving and returning for a second helping later on.
Cocaine is another natural drug, which surprisingly, many people don't realise is natural. Found in the coca plant, it has been used for centuries for anything from tiredness and lack of motivation to altitude sickness. Natives in areas where there is a culture of use still chew the leaves of the coca plant on a daily basis to cope with high altitudes and boost their energy.
Today, cocaine is only usually used by dentists as a mouth numbing anesthetic. This is not because it doesn't have useful pharmacological effects, but because centuries of abuse of the drug have all but caused it to be removed from the market and replaced by similar compounds that don't have a recreational side effect yet still have therapeutic benefits.
Digoxin is a powerful poison, derived from foxglove. Foxglove is known for its beautiful tubular flowers, which hang from a tall stem and sway in the wind. It's fairly common to see it growing in the wild or around cottages where it has been intentionally cultivated for its beauty. It's also the source of digitalis glycosides however, which are dangerous heart poisons.
The narrow therapeutic window of digoxin has caused it to be dropped from use in many situations, but it is still one of the only effective treatments for certain types of heart disease. In particular, it is often used after other treatments have failed. It has many harmful side effects, even when used properly.
Used for Parkinson's disease, restless leg syndrome, and other conditions that are treated with dopamine, l-dopa is an effective, safe, and preferred treatment over drugs like cabergoline and pramipexole. Unlike those drugs, it can be derived from nature because it is found naturally in many plants, like mucuna pruriens.
However, don't let l-dopa's safe treatment reputation and natural origins fool you. In too high a dosage it can cause many side effects including psychosis, hypersexuality, and even cause strange effects like compulsive gambling and out of control shopping. It may be derived from nature, but given that it is converted into dopamine, and dopamine is an important neurotransmitter, it can even lead to changes in personality and promote schizophrenia in those who are genetically susceptible to it.