The Evolutionary Battle of Natural Chemicals: From Toxins to Therapies

Exploring the origins and functions of natural chemicals, from toxins to psychedelics, and their potential as both weapons and medicines.

Humans have long relied on a variety of natural chemicals for various purposes, from enhancing flavor in food and drink to alleviating pain and altering perception. These chemicals, such as caffeine, capsaicin, and morphine, have become an integral part of our lives. However, the question remains: why do plants, mushrooms, microbes, and even animals produce these chemicals with life-saving, life-enhancing, and even life-ending properties? As an evolutionary biologist, my research aims to shed light on this intriguing phenomenon and uncover the potential risks and benefits of these chemicals.

The Dual Nature of Natural Chemicals

Many natural chemicals exhibit a dual nature, serving both as deadly toxins and valuable drugs. For instance, botulinum toxin, known as one of the deadliest natural toxins, is also the active ingredient in the popular anti-wrinkle drug Botox. Similarly, the chemical used by bread mold to fend off bacteria is the wonder drug penicillin. This duality is also seen in caffeine, which acts as a potent insecticide in plants while being the most widely consumed psychoactive drug in the world. The poison made by yew trees to deter caterpillars is also the powerful anti-cancer drug Taxol, and the venom of cone snails contains a potent painkiller called ziconotide.

Intercepting Chemical Weapons in “The War of Nature”

These examples suggest that humans have inadvertently intercepted chemical weapons deployed in what Charles Darwin referred to as “the war of nature.” Many of the chemicals we use and abuse have evolved to enhance the survival odds of the organisms that produce them or consume them through their diet or microbiomes. This intricate battle between organisms has shaped the evolution of these chemicals, making them seemingly tailor-made for our use.

Personal Reflections on Toxins and Psychedelics

The personal experiences of the author, whose father passed away from alcohol use disorder, provide a poignant perspective on the impact of natural toxins. The yeast toxin ethanol, which led to his father’s demise, serves as a reminder that humans have been both beneficiaries and victims of the chemical warfare in nature. This realization prompted a deeper examination of the evolution of toxins and their parallels with the rise of natural psychedelic chemicals.

The Rise of Natural Psychedelics

Natural psychedelics, such as psilocybin, DMT, mescaline, and ergot alkaloids, have been used by indigenous peoples for centuries for medicinal and spiritual purposes. These chemicals, which bind to serotonin receptors in the brain, are now being explored as transformative therapies for mental health disorders resistant to conventional treatments. However, the evolutionary origins and functions of these psychedelics remain a subject of ongoing research.

The Defense Mechanisms of Psychedelic Chemicals

Just as toxins serve as defense mechanisms, natural psychedelics may also function as chemical weapons. The extreme bitterness of psychedelics may deter animals from consuming them, acting as a defense in itself. Grasses in the Phalaris genus, for example, produce 5-Meo-DMT and DMT, which make them unpalatable to grazing herbivores. Additionally, the blue coloration of injured magic mushrooms, caused by the transformation of psilocybin into psilocin, may disrupt the digestive tracts of potential predators.


The study of natural chemicals, from toxins to psychedelics, offers valuable insights into their evolutionary origins and functions. While psychedelics show promise as therapeutic agents, it is crucial to subject them to rigorous scientific scrutiny through clinical trials. Understanding the natural functions of these chemicals can help us navigate their potential as drugs and evaluate the risks they may pose. Nature’s pharmacopeia is a complex battleground, and by delving into its intricacies, we can uncover both the wonders and the dangers of these remarkable compounds.






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