Colds with a runny nose and yellow phlegm are usually caused by a viral infection combined with a bacterial infection. Colds are viral infections that are easily caused by seasonal changes, exposure to cold or contact with a person who has a cold. It is usually characterized by runny nose, sneezing, nasal congestion, cough and other discomforts. Colds are usually clear nose, dry cough or a small amount of clear sputum, usually about a week to heal. In some patients, weak body, poor immunity, or improper care during the cold, may lead to respiratory tract combined with bacterial infections to prolong the course of the disease, and symptoms such as purulent nasal discharge, frequent coughing with yellowish purulent sputum, and so on. If symptoms are severe, antibiotics such as amoxicillin and cefixime are needed to fight infection. Clear runny nose and yellow sputum can also be caused by other diseases. If the symptoms are not relieved or aggravated, it is recommended to go to the hospital specialist, complete the examination, clarify the cause of the disease, and follow the doctor’s instructions to avoid unauthorized use of drugs, so as not to aggravate the condition.