The Times’ Amanda Schaffer covers a retrospective of public health posters on display at the National Academies until December 19th, 2008. The catalog (pdf) is online.
“No home remedy or quack doctor ever cured syphilis or gonorrhea. See your doctor or local health officer.”
You could replace “syphilis or gonorrhea” with just about anything! Perhaps we should reissue this poster to deal with the modern quacks!