Spacer is an auxiliary tool for the inhalation of medication aerosols (pMDI) for the treatment of asthma, and is used to store the medication aerosol. pMDI sprayed mist is stored in the spacer, and the child inhales the medication from the spacer, which can increase the efficacy of pMDI and reduce its side effects. There are many kinds of fog storage tanks, both large and small, metal and plastic products, each with its own advantages and disadvantages. Generally speaking, as long as the correct use, the effect is not much different. pMDI drug mist through the fog canister, drug particles and the air in the canister fully mixed, to solve the problem of spraying and inhalation is not synchronized, and can be repeatedly inhaled, the inhalation of drug mist can fully enter the lungs, the irritation of the oropharynx is reduced accordingly. The large volume of the fog canister is not convenient to carry, the small volume is convenient to carry, but the efficacy is not as large fog canister. Fog canisters are mainly used for children with asthma and some elderly patients who cannot cooperate well with inhalation and hand movements, or patients who have significant local side effects in the throat after using pMDI, especially for inhaled corticosteroids, using fog canisters will significantly reduce the local side effects of inhaled glucocorticosteroids and potential systemic side effects. Usually a face mask is required with the nebulizer for children under 5 years of age, and an oral device nebulizer is available for children over 5 years of age and adults. The pMDI + Spacer inhalation method is: first open the protective lid of the pMDI, shake the drug up and down fully 5-6 times, insert the pMDI into the insertion port of the fog canister, the mouth and nose mask of the fog canister knock the child’s mouth and nose, the pMDI must face up, press the pMDI to make the sprayed drug stored in the canister, and then the child inhales naturally, the drug is inhaled into the airways and lungs. Only one press can be made at a time, and about 15 breaths (or 30 seconds). Finally, after inhalation, mouth and face should be rinsed to remove the drug deposited in the oropharynx and face. pMDI with Spacer is most effective when breathing calmly and least effective when crying, if the child cannot cooperate, the drug can be inhaled during sleep. General storage jar once a week or so to clean, cleaning can be washed with detergent, but must be rinsed with water, and then dried naturally, do not wipe the inner wall, so as not to produce static electricity affect the efficacy of treatment. If the storage jar has to flap without damage, do not need to replace.