As the number of states increase where medical and recreational cannabis use is legal, so does the importance that physicians discuss with patients the effects of cannabis on those with asthma. A new survey in Annals of Allergy, Asthma and Immunology, the scientific journal of the American College of Allergy, Asthma and Immunology, shows that of those who used cannabis, about half smoked it while a third vaped—both “inhalation routes” likely to affect one’s lungs.