A patent medicine, also known as a proprietary medicine or a nostrum (from the Latin nostrum remedium, or "our remedy") is a commercial product advertised to consumers as an over-the-counter medicine, generally for a variety of ailments, without regard to its actual effectiveness or the potential for harmful side effects. The earliest patent medicines were created in the 17th century. They were most popular from the mid-19th century to the early 20th century, before the advent of consumer protection laws and evidence-based medicine. Despite the name, patent medicines were usually trademarked but not actually patented, in order to keep their formulas secret.