Onions, myths, beliefs, fashion and reality in asthma.

Some myths and unsupported beliefs about asthma are very popular and enjoy general public acceptance and fairly strong support on the Internet. Onions for cough; dairy products avoidance for asthma; and some other popular myths are reviewed, along with some other medical and mixed (popular and medical) myths comparing their popular and scientific support. Classifying medical statements as realities or unsupported beliefs is a hard and serious work nowadays addressed by Evidence Based Medicine methods, which are not devoid of the influence of medical fashion: the medical community is more prone to accept fashionable statements compared to non-fashionable or old-fashioned statements.