Patients can not smoke before the morning physical examination, because smoking before the morning physical examination, it is easy to make some chemical components contained in tobacco into the body, such as tar, incomplete combustion and carbon monoxide, etc., directly stimulate the respiratory mucosa, causing different degrees of congestion, edema, inflammatory secretion exudation changes, easy to make the respiratory mucosa damaged, and thus infected by viruses, bacteria and other pathogens. At this time, it is easy to cause an inflammatory response, leading to the appearance of inflammation of the respiratory tract, so that the immunity continues to decline, resulting in the results of the physical examination is affected. Therefore, you can not smoke before the morning physical examination, and you can not eat breakfast before checking liver function, kidney function and other examination items, and you have to fast.