GAROUA, Cameroon—Not long ago, a Dutch neurobiologist announced a surprising discovery: A root used by rural West African healers to treat pain contains an apparently natural version of a man-made opioid.
The root from northern Cameroon had such high levels of a painkiller called tramadol that mice given an extract and placed on a hot plate didn't feel their feet burning at first.
A year later, German rivals came up with a different explanation for the unusual plant. Inexpensive, imported tramadol is so heavily abused in northern Cameroon that it seeps from human and animal waste into the groundwater and soil, where vegetation absorbs it, wrote Michael Spiteller and Souvik Kusari, chemists at the University of Dortmund.
Farmers in Northern Cameroon told the researchers that they take double or triple the safe dosage, and feed tramadol to cattle to help them pull plows through the scorching afternoon sun.