There is no such thing as the fastest and most effective way to expectorate in infants. Expectoration in infants requires different treatments depending on the cause. If a baby has phlegm, it can be caused by upper respiratory tract infection, sinusitis, bronchial asthma, etc., and can be treated with drugs such as amoxicillin or surgery. 1. Upper respiratory tract infection: If it is caused by a virus, usually no special medication is needed. If combined with bacterial infection, should follow the doctor to use cefixime, amoxicillin and other antibacterial drugs; if caused by influenza virus, can be applied to oseltamivir and other antiviral drugs treatment. If necessary, inhalation of acetylcysteine solution can be applied to nebulize the treatment, in order to promote the discharge of sputum. 2. Sinusitis: Runny nose, nasal congestion, headache, fever and other symptoms can occur, due to postnasal drip will cause infants to have phlegm. Generally, you can use saline to wash the nose, and in the acute stage, you can take azithromycin and other drugs to control the infection. If conservative treatment is ineffective, nasal surgery can be taken. 3. Bronchial asthma: cough, chest tightness, wheezing as prominent symptoms, some children have fever. Generally need to avoid allergens, at the same time with budesonide and other nebulizer treatment. Infants with phlegm, there may be other reasons, such as pneumonia, it is recommended to consult a doctor in a timely manner to identify the cause, corresponding treatment, the above medication as prescribed by the doctor.