Walter Lewis


Ethnobotanist: World expert on airborne and allergenic pollen and famous for targeting medicinal plants in the tropical rain forest.

"Do what you enjoy and go where your heart takes you."

Holding his half-full gourd of “chicha,” Walter Lewis smiles, wishing he didn’t have to drink another drop. It tastes so sour, like a combination of yogurt, warm beer and mashed potatoes. But the headman — the apu of the Achuar Jivura village in the Peruvian Amazon jungle — is looking him right in the eye. To refuse this friendship ceremony drink would be an insult to his hosts.

Lewis takes another look at the yellowish liquid in his gourd. He knows that Achuar women make chicha by chewing a kind of cassava root and spitting it into a huge bowl. Then they let it stand for a while to ferment. The air in the open hut is wet and hot. Lewis feels his shirt stick to the sweat on his back as he turns to glance at his wife, Memory, sitting among the women just outside the men’s circle. A smouldering cooking fire gives everything the smell of smoked fish. The forest outside is alive with shrieking jungle birds while inside the hut, pet parrots, monkeys and dogs squawk and bark. A crowd of gawking, naked children surrounds the Lewises. “We are the zoo,” thinks Lewis as he takes a final sip of the brew like a good ethnobotanist.

The Lewises have travelled to the Peruvian jungle in search of plants that might yield new drugs. They are ethnobotanists and they specialize in communicating with native peoples around the world to learn about their traditional medicines. Mariano, the headman, is telling Walter about the healing powers of a certain plant whose roots are used to help women through the final stages of childbirth.

While Walter is talking to Mariano, Memory notices a big grin on the face of an old woman in the back row. In Achuar culture, women do not sit with the men but have their own special area within the hut. Memory quietly goes to talk to the old woman, who turns out to be Mariano’s auntie. She takes Memory outside to show her the plant Mariano is talking about, all the while telling her how men don’t know much about this medicine, since it’s used strictly by women. When Memory sees the plant, she learns that it’s not the root the Achuar use but the leaf. On closer inspection later, Walter discovers that it’s not the leaf that has the medicinal quality but an ergot-like fungus growing on the topmost leaves of the plant.

The Lewises credit many of their discoveries to the way they work as a team. If Walter had been in the jungle on his own, perhaps he never would have discovered this medicine. As a man he would probably not have talked to the women of the tribe, and he would have embarked on a futile search for the active ingredient in the roots of the plant.

As a young scientist ...

When Walter was 12 his dad asked him what he wanted for his birthday. The Lewis family lived in Victoria, British Columbia, and Walter was fascinated by an uncle who had a plant nursery in the countryside. Walter told his dad he’d like a greenhouse for his birthday, and his father gave him one. It was made of wood and glass and was about three metres long and two metres wide, with planting benches on each long wall. Walter’s uncle taught him how to grow roses from cuttings. The next summer Walter began selling his roses in Victoria.

His mom and dad wanted him to become a dentist. Walter went to Victoria College (which later became the University of Victoria) to study toward dentistry, but he took extra botany courses on the side to satisfy his curiosity about plants. After second-year university he announced to his parents that he would become a botanist, not a dentist.

Read Walter Lewis's answers to questions...The Science