Time Capsule

In the early evening of Oct. 20, 1909, U.S. government agents set up a stakeout on the Tennessee state line. They were watching for a truck coming from the Coca-Cola plant in Atlanta on its way to the bottling plant in Chattanooga. When it arrived they intercepted the truck and seized its cargo—40 barrels and 20 kegs of Coca-Cola syrup. The seizure was made under the recently passed Pure Food and Drug Act.

The government charged the company with marketing and selling a beverage that was injurious to health because it contained a harmful ingredient. No, it wasn't cocaine, which never amounted to more than a trace in the beverage in its earliest years. It was caffeine.

The United States and Coca-Cola attorneys would meet in court in Chattanooga in 1911 under the federal lawsuit The United States Government v. Forty Barrels, Twenty Kegs Coca-Cola. Coca-Cola was described in the suit as a beverage that produced serious mental and motor deficits.

The impetus behind the lawsuit was Harvey Washington Wiley, head of the Bureau of Chemistry of the U.S. Department of Agriculture. He had long been a vocal opponent of caffeine and was especially critical of its inclusion in the popular beverage. At the beginning of the 20th century, Coca-Cola marketed the stimulant properties of the drink, noting that it "invigorated the fatigued body and quickened the tired brain." Wiley had testified before Congress that caffeine was a poison and a habit-forming drug. He was not fond of coffee or tea but was less critical of those drinks because the caffeine was an indigenous ingredient. He opposed the sale of Coca-Cola on two grounds: the caffeine was an added ingredient, and the beverage was marketed to children.

As the Coca-Cola Company prepared to go to trial, its attorneys realized that the extant research on the effects of caffeine was mostly animal research; they needed research that spoke to the effects on humans. They asked famed psychologist James McKeen Cattell of Columbia University if he would do the work, but he declined. Accepting money from a corporation to do research that the company hoped would be favorable to its legal and commercial needs raised concerns about scientific integrity. Eventually Coca-Cola found a willing participant in one of Cattell's recent doctoral students, Harry Hollingworth, an instructor at Barnard College who needed the money that the research would provide. Looking back on his life, Hollingworth wrote that he accepted the offer because at his age he "had as yet no sanctity to preserve."

Because the trial was about to begin, the results were needed in a matter of weeks. Hollingworth planned a series of three studies that were completed in 40 days. The studies were masterfully designed and are still cited today because of their methodological sophistication.

The laboratory for the study was a six-room Manhattan apartment rented specifically for the research. Subjects were selected based on good health and represented a range of caffeine consumption from "abstainers" to "regular users." The caffeine was administered in a variety of doses that bracketed the amount of caffeine a moderate drinker of Coca-Cola might consume in a day. Nearly 20 tests were involved in the three experiments including tests of cognitive, sensory and motor abilities (e.g., hand steadiness, reaction time, mental calculations, color discrimination, speed in a cancellation task).

The first week of the double-blind studies involved no caffeine in order to get baseline data on the subjects and the dependent measures. When the caffeine administration began, it was given by capsule. Some subjects got a placebo, also by capsule so that no differential taste cues were present. The final study, which lasted a week, used Coca-Cola syrup, some with caffeine and some without. The studies were run during the day by Leta Hollingworth, Harry's wife, who would use the money he earned from Coca-Cola to pursue her doctorate in psychology at Columbia. Harry would join her in the evenings for data analysis in preparation for the trial.

The trial was already under way when the studies were completed. Hollingworth testified in the third week, the ninth scientist called on by the Coca-Cola attorneys. His research results were quite favorable for the company. He testified that Coca-Cola appeared to be a mild stimulant both for motor and cognitive performance, and he reported that he found no evidence of the deleterious effects on mental and motor performance alleged by the government.

The case never reached a jury. In the trial's fourth week the judge dismissed the case, siding with the Coca-Cola attorneys that caffeine was not an "added" ingredient but an "essential constituent" of the drink. Thus the charges of the harmfulness of caffeine were never decided. The government appealed the case and lost. The government then took the case to the Supreme Court in 1916 and won. Coca-Cola reduced its caffeine content but did not eliminate it, and the company paid all court costs as part of the settlement.

Hollingworth published the results of his caffeine studies in a lengthy monograph in 1912. He never returned to psychopharmacological work again. But the Coca-Cola research set him on a life course as an applied psychologist of considerable reputation and wealth. His notable research in the field of advertising and other related studies in the psychology of the workplace established him as a pioneer of industrial/organizational psychology.

The papers of Harry and Leta Hollingworth are part of the manuscript collections of the Archives of the History of American Psychology at the University of Akron. Wiley's papers, and those of James McKeen Cattell can be found in the collections of the Library of Congress.


Ludy T. Benjamin Jr., PhD, is professor of psychology and educational psychology at Texas A&M University.

Further reading

Benjamin, L.T., Jr., 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.L. (1912). The influence of caffeine on mental and motor efficiency. Archives of Psychology, No. 22, pp. 1–166.


Pendergrast, M. (2000). For God, country, and Coca-Cola: The definitive history of the great American soft drink and the company that makes it (2nd ed.). New York: Basic Books.