Coughing up sputum with occasional blood spots may be the presence of respiratory and circulatory diseases. 1. Diseases of the respiratory system: bronchiectasis, tuberculosis, pneumonia and lung cancer can cause symptoms such as coughing up bloody sputum. The most common cause of coughing up bloody sputum is tuberculosis, which is caused by damage to blood vessels due to erosion of the lesions. 2. Diseases of the circulatory system: Coughing up bloody sputum is usually triggered by mitral stenosis, congenital heart disease, and pulmonary heart disease, and is related to lung congestion or rupture of capillaries in the lungs. Especially in the late stage of mitral stenosis, pulmonary infarction is easy to cough up bloody sputum. If you often have blood in sputum, you must immediately go to the hospital for examination, do not delay, so as not to cause delays in the disease, or even life-threatening.