There are many triggers for asthma, especially closely related to environmental factors, such as sudden exposure to cold air, animal fur, smoke, pollen, etc., which can cause an acute asthma attack. Therefore, asthma patients should learn the use of first-aid medicine, and some patients should also carry it with them. Short-acting beta2 agonist aerosols such as salbutamol and terbutaline can be inhaled during an acute asthma attack, 2-4 sprays each time; if the symptoms are not relieved, the spray can be repeated after 20 minutes; those who cannot be relieved after 3 repetitions should go to the hospital in time for emergency treatment. Short-acting β2 agonists are a kind of drugs to relieve asthma symptoms rapidly, which can relax the tight smooth muscles around the bronchial tubes, thus temporarily expanding the spasmodic airways, and can take effect within 3~5 minutes, and the effect lasts about 4 hours.