Innumerable vegetable substances, often in the form of powders or teas made from green plants, have been used as popular remedies for diabetes throughout the world. As one example, eucalyptus leaf tea attracted so much notice in some regions that it was investigated at the Physiatric Institute at the special request of the National Research Council, with negative results.1In 1925, Professor Durig of the University of Vienna became impressed with the benefits of blueberry leaf tea as used for diabetes among the Alpine peasantry2to such an extent that he suggested an investigation of the question by Dr. Richard I. Wagner, a chemist in his laboratory. Brief summaries of the results of physiologic experiments were published by Dr. Wagner in collaboration with Mark,3and of clinical observations in collaboration with Mark and Eppinger.4The blueberry leaf tea showed distinct but variable influence on the alimentary