Old wives tales and home remedies

Have you ever been blamed when your child became sick because of an old belief that has been disproved? Has anyone tried to promote a home remedy as a cure that could be dangerous? I know not all old wives tales are this way, there is nothing wrong with harmless gender prediction, weather prediction, etc, and I'm not talking about holistic medicine that has been studied. I am only talking about situations where there is no medical basis or study or the belief has been disproved.