Human beings have long depended on medicines from Nature to prevent and treat illnesses, and today the World Health Organization (WHO) estimates that up to 80% of the global population still relies on plants for primary health care.

For many of the 150 million tribal peoples, Nature provides a potent pharmacy that they can rely on, thanks to their detailed botanical knowledge; the upshot of a profound attunement to their ecosystems for thousands of years.

For example, the Yanomami of the Amazon drink the juice of the woody cat’s claw vine to relieve diarrhoea, and apply the bark of the copal tree to treat eye infections. And the Shuar of Ecuador and Peru use no less than 100 different species of plants solely for stomach ailments.

Another Peruvian tribe, the Matsigenka, rely on herbs stored in water-filled pots to protect their babies. They think of many illnesses as foul-smelling ‘odours’ or ‘vapours’ that have risen from the bowels of the Earth, so, as anthropologist Glenn Shepard writes: “the fragrance of Myrtaceae species and the ginger-like sedge root create an aromatic force field around the child which keeps malodorous spirits at bay”.

Thousands of years of patient observation and experimentation are evident too in the Innu people’s awareness that earache can be successfully treated with the inner scrapings of beavers’ scrota. “There are medicines out there that I know about,” said an Innu man. “In the country I am an environmentalist and a biologist.”

In tribal communities the role of ‘biologist’ is often performed by shamans: highly revered mediators between the living and the supernatural worlds, they combine the diagnostic and curative power of plants with spiritual healing. They use the psychoactive properties of plants to induce altered states of consciousness which allow them to commune with the spirits of natural phenomena in order to determine the cause of their patients’ illnesses and ask advice on the appropriate treatment. “When for the first time you sniff the powder from the yãkõanahi tree, the xapiripë spirits begin to gather around you. Gradually, they reveal themselves,” says Davi Kopenawa, a Yanomami shaman from Brazil.

For the Yali shamans of West Papua’s central highlands, certain plants are so powerful that they are able to drive ghosts from villages and rats from fields, and ensure the arrival of rain or the success of a hunting trip. “The Yali excel as ecologists,” says William Milliken, an ethnobotanist currently based at the Royal Botanic Gardens in Kew, London. “One elder taught me about the magic plants of his world. So secret and powerful were the plants, he sometimes only whispered their names so as not to speak them aloud.”

It is the oral traditions of tribal societies that have trained generations of shamans. Tribal languages are those of the land, suffused with vocabularies that contain complex geographical, geological, medicinal and climatic information. The Kallawaya, highland farmers and travelling healers in Bolivia who have a vast knowledge of wild plants and their therapeutic uses, have their own ‘secret’ language, called Machaj Juyai, believed by some to be the language of the Inca kings. Encoded within this tongue is medical knowledge that has been handed down from father to son. Of the 7,000 languages in the world, however, around 4,000 are now endangered. “Every language and culture shows us something about the way a people has evolved to deal with the world,” says linguist Daniel Everett. “So when a language dies, we lose ways of life, solutions to problems and classifications of plants and animals.”

Were it not for the plant knowledge of tribal peoples, many vital medicinal compounds might still be unknown. Certain plant products, used initially as poisons by South American Indians, have become important in Western medicine. One example is the poison curare. Used on the tips of blowgun darts to render prey immobile, it has been appropriated as a muscle relaxant for humans and has made possible techniques such as open-heart surgery. As it is widely believed that the medicinal value of many plant species is as yet unknown to Western scientists, it makes sense to place greater value on the knowledge and experience of peoples who have been studying their flora and fauna for millennia.

Valuable as the botanical knowledge of tribal peoples is, perhaps even more so is their holistic approach to health. Wellbeing is seen not just as the absence of illness, but as a state of emotional, physical and spiritual harmony. Man is not an island: humans are dependent for their health on harmonious connections to each other and to the Earth. “The environment is not separate from us,’ says Davi Kopenawa. ‘We are inside it and it is inside us.”

This is a philosophy that takes into account the whole person, as opposed to the more reductive approach of allopathic medicine, which tends to consider an individual as composed of separate parts. As the industrialised world becomes increasingly aware of the adverse physical and mental effects of separation from Nature – one study has shown that gall-bladder surgery patients who had views of Nature from their hospital beds took less pain medication than those who had views of a concrete wall – the need to integrate the genius of Western medicine with the holistic understanding of tribal peoples becomes ever more urgent. And with new pathogens threatening to cross the species divide, the hope is that new medicinal plant compounds will be found.

Calanolide A, a unique chemical produced by the Bintangor tree deep in the rainforests of Borneo, has recently been isolated; it may be effective in inhibiting the proliferation of the HIV virus. Coral reefs are also sources of medicines being developed to treat cancer, arthritis and heart disease; a recent study by Australian researchers suggests that coral produces compounds that act as a sunscreen, which could be developed for human use. And a chemical called kainic acid, found in Japan’s coral reefs, is being used to investigate Huntington’s chorea. As the naturalist E.O. Wilson once wrote, “We do not even know why we respond in a certain way to other organisms, and need them in diverse ways so deeply.”

Ironically, just as Western medicine is beginning to rediscover the value of natural remedies, so the world’s rainforests and coral reefs are being destroyed and plants are becoming extinct. Botanic Gardens Conservation International estimates that over-harvesting and loss of habitat threatens the survival of over 50,000 currently known medicinal plant species. As the habitats that are the richest in biodiversity tend to be those still under the stewardship of tribal peoples (the Jarawa, for instance, inhabit the last remaining tracts of virgin rainforest in the Andaman Islands), it follows that the best way of protecting these precious medicinal plants is to secure the land rights of their guardians, the tribal communities.

As a child, I suffered from occasional warts on my thumb. These were treated by my Welsh grandfather, an eminent eye surgeon. His technique? He cut an apple, rubbed the wart with one half and buried the other in a sunny spot in the garden, just below the orchard. The wart would disappear within days. A placebo effect? Perhaps. But isn’t this what the anthropologist Dan Moerman refers to as the ‘meaning response’ – the human mind responding physiologically to curative manipulations that are meaningful to the individual? These subtle and symbiotic powers of mind, body and Nature are perhaps still far better understood by shamans and traditional healers than by many ‘modern’ medical practitioners.

If we can find a painkiller from Ecuadorian frogs that is 200 times as potent as morphine, if we can learn that there are anti-cancer properties in aquatic invertebrates, we can only guess at what other powerful natural panaceas lie within the tropical forests, in the depths of the ocean, or in the icy reaches of the Arctic. And the ancient languages of the world’s tribal peoples are no doubt laden with knowledge invaluable for everyone.

Joanna Eede is Editorial Consultant with Survival International and creator of We Are One, a book celebrating the world’s tribal peoples.