Smoking after a fracture is not conducive to fracture healing and will slow down the rate of fracture healing. Smoking releases a range of toxic and harmful substances (e.g. aldehydes, nitrogen compounds, carbon monoxide, nicotine and other substances). These substances affect the lungs and respiratory tract, affecting the transport of oxygen in the blood, thus causing a lack of oxygen to the surrounding tissues. Secondly they can also cause spasms in the blood vessels, resulting in a reduced blood supply to the fracture site. Blood supply is the most important factor in the healing of a fracture. Therefore, smoking slows down fracture healing. In addition to this, smoking also has the risk of causing cancer. So smoking should not be done during a fracture or not, whether it is active or passive smoking. Patients are advised to quit smoking in time to promote recovery.