1930s
periods are no longer a pain
In the early 1900s, Midol was sold as an ordinary pain reliever like Tylenol or Advil (One Midol ad from 1911 actually includes a man examining the bottle!) Midol wasn't advertised as a menstrual product until the 1930s, when it was re-branded to compete with Kotex's menstrual pain reliever, Kurb, which also came out in the '30s.
Early advertisements for menstrual pain relief products would usually allude to a woman's period with subtle words or phrases instead of openly addressing it. For example, Kurb was marketed to "lessen pain and discomfort on certain days" and a 1948 Midol ad claimed to relieve "functional periodic pain" like cramps, headaches and "blues." These symptoms are collectively called "PMS" today--a term that didn't exist until the late 1970s.
In fact, lots of vintage ads for menstrual pain relievers suggested that women were moody before or during their periods. Midol ads from the 1940s claimed the product could turn a "dull day into a gay day. " One product marketed for menstrual pain relief around the same time was actually called "Gay." Of course, this all happened during a time when gay usually meant "happy"--not "homosexual."