According to the APA‘s Today in the History of Psychology site, on March 16th 1911 the trial of the United States v. 40 Barrels and 20 Kegs of Coca-Cola began.
The ordeal began when the U.S. Food and Drug Administration seized a shipment of Coca-Cola syrup in 1909 based on the suspicion that caffeine was harmful.
The trial featured testimony from psychologist Harry Hollingworth who examined the effects of caffeine on mental function. Although the research was funded by the Coca-cola company, Hollingworth had several stipulations in his contract including the right to publish his results, regardless of their outcome.
Coca-cola would be acquitted of the charges on June 13, 1914.
For further information on Harry Hollingworth, the trial and the Coca-cola company see:
Benjamin, L. T. (1996). Harry Hollingworth: Portrait of a generalist. In G. A. Kimble, C. A. Boneau, & M. Wertheimer (Eds.) Portraits of pioneers in psychology, Vol. 2, 191-135. Washington, DC: American Psychological Association.
Benjamin, L. T., Rogers, A. M., & Rosenbaum, A. (1991). Coca-Cola, caffeine, and mental deficiency: Harry Hollingworth and the Chattanooga trial of 1911. Journal of the History of the Behavioral Sciences, 27, 42-55
Hollingworth, H. (1912). The influence of caffein on mental and motor efficiency. NY: The Science Press.
Pendergrast, M. (2000). For god, country and coca-cola: The definitive history of the great american soft drink and the company that makes it. Basic Books.
Poffenberger, A.T. (1957). Harry Levi Hollingworth: 1880-1956. The American Journal of Psychology, 70, 1, p. 136-140.
Young, J.H. (1983). Three southern food and drug cases. The Journal of Southern History, 49, 1, p. 3-36.