Aristolochia clematitis, (European) Birthwort, is a twining herbaceous plant in the Aristolochiaceae family, which is native to Europe. The leaves are heart shaped and the flowers are pale yellow and tubular in form. The plant seeks light by ascending the stems of surrounding plants.
Just after the end of World War II, family doctors in north-west Bulgaria noted a high incidence of kidney disease but only in some areas. The disease occurred only in villages and small towns; it did not affect cities. Afflicted villages were separated by no more than a couple of kilometres from disease free villages and, though often found to affect members of the same family, it was shown that it was not hereditary.
A Serbian microbiologist, called Ivic, theorized that seeds of the plant could be contaminating the wheat used to bake bread, in the home. It is said that he was aware of reports of poisoning in horses that had grazed Aristolochia clematitis. After conducting trials with rats and rabbits which showed that Aristolchia seeds caused both kidney damage and cancer, Ivic published full details of his careful research in 1969. For reasons which are, today, unknowable, his work was largely ignored and efforts continued to focus on the mycotoxin theory or some other environmental factor.
There are still people, living in the afflicted areas, who blame the water for taking the lives of members of their community.