After the cold will cause coughing, coughing up sputum, if the sputum is black, mainly due to frequent smoking or work, living environment black dust is more, inhaled into the trachea and lungs after not timely discharged, when the cold will stimulate the trachea to appear too much secretion, the black material will be discharged with the sputum, thus forming black sputum. If there is abscess in the lungs, bronchial dilatation or tuberculosis, it may cause a small amount of bleeding in the lungs and trachea, which is not discharged in time, and then discharged along with the sputum, and black sputum may also appear. This situation needs to be actively treated with cough suppressing and phlegm dissolving drugs, usually also need to pay attention to daily protection, it is best to quit smoking, with the above chronic diseases need to be actively treated.