It is certain that lung cancer is not contagious to people, whether in early or late stage, with or without coughing and blood in sputum. Because lung cancer itself is not an infectious disease, not an infection caused by bacteria or virus, but a genetic mutation of normal cells due to various reasons, such cancer cells will not spread to others through coughing, sweating, saliva and breathing. Even if cancer cells enter other people’s body due to various accidental factors, they will not survive in the body because of the strong immune clearance ability in other people’s body. Therefore, family members of cancer patients can rest assured that lung cancer is not contagious and should take good care of lung cancer patients.