Having a cough and coughing up sputum is mainly caused by infections of the respiratory tract. If the coughing up sputum is smelly, it is considered to be caused by lung abscess, bronchiectasis, and various severe purulent bronchitis and pneumonia are also likely to cause it. E. coli infection, Klebsiella pneumoniae infection, and Streptococcus pneumoniae infection are the main causes. Since Streptococcus pneumoniae infection causes lobar pneumonia, rusty sputum is coughed up. If the infection is caused by Klebsiella pneumoniae, red colloidal sputum will be coughed up. It is necessary to go to the hospital for routine blood tests, to take chest X-ray, to do sputum tests, and then to use more sensitive drugs for treatment under the guidance of the doctor according to the test results. If the infection is caused by Streptococcus pneumoniae, penicillin and cephalosporins are preferred.