Patent medicine is the term given to various medical compounds sold under a variety of names and labels, though they were for the most part actually trademarked medicines, not patented. In ancient times, such medicine was called nostrum remedium, "our remedy" in Latin, hence the name "nostrum"; it is a medicine whose efficacy is questionable and whose ingredients are usually kept secret.
The trade cards are small, colorfully illustrated advertising cards touting a particular medicine and its many cures. The illustrations often have little to do with any of the ailments purported to be cured. They were pure advertising and very collectible. The era of patent medicine began to unravel in the U.S. with the passage of the first Pure Food and Drug Act in 1906.