If a cold is still not well after three days of injection and medication, it may be caused by insufficient course of medication, irrational use of medication, or comorbidities. It is recommended that further examination be carried out and that anti-disease, anti-virus and anti-infection medications be given. 1. Insufficient medication: Colds are self-limiting, and if the symptoms are mild, they can be treated without medication, and may get better in a week or so. For example, the common cold is mostly cured in about a week, the cold injection and medication for three days with a relatively short period of time, may not be able to fully recover, it is recommended that symptomatic treatment. 2. Unreasonable medication: Patients with the common cold should pay attention to rest, drink more water, and avoid secondary bacterial infections. If accompanied by bacterial infection, simply taking antiviral drugs may not be effective, if necessary, with anti-infective drugs such as amoxicillin, roxithromycin and other drugs treatment. 3. Combined complications: If the cold is not treated in time, or the condition is further aggravated, a variety of complications may occur. Such as acute sinusitis, acute otitis media, pharyngeal wall abscess, acute pharyngitis, acute pneumonia, etc., can be given to cold and clear heat particles, cephalosporin, etc., if necessary, with intravenous infusion treatment. If the symptoms of cold and flu are mild, it is recommended to pay attention to daily care, and the symptoms can be gradually reduced with the passage of time. If the symptoms are combined with other complications, it is recommended to go to the Department of Infectious Diseases of the hospital in time, under the guidance of the doctor’s treatment. Drugs should be used under the guidance of a professional physician, and should not be used on their own.