The expression arose around WW2 and refers to Bex and Vincent's Powders that were available at corner stores and used in excessive amounts from large percentage of the population.
In the 1950's it was widely believed that most housewives were addicted to the powders to get them through the drudgery and hard work of the day, hence the expression.
I found a blog that contained vast amounts of information about this now vanished addiction. Click here for the Bex story
The old advertisements certainly look aimed at women.