Before the Pure Food and Drug Act of 1906, makers of patent medicines were not required to label the ingredients of their products. Treatments for babies' colic, "women's disorders," and almost any imaginable ailment were marketed to users who had no way of knowing their ingredients or the proportions of opium, cocaine, alcohol, or other drugs in those medicines. At best, many of these concoctions were worthless as medical treatments; at worst, they were addictive and even deadly.

Responding to a growing recognition of the problems and implications of addiction during the late 1800s, the media and medical groups began to speak out about the dangers of many of these substances. The public became interested in what their medicine bottles contained. Before that time, if consumers of these medicines had known the ingredients in their medicines, few of them or their physicians would have understood...