<s>[INST] I meant to ask this in my previous question, but may as well create a new one. I've always been curious about the "coughing up blood" symptom of lung cancer. Is this a normal involuntary cough? i.e. having the URGE to cough as opposed to forcing yourself to cough. Thanks again [/INST] Thanks for your question on HCM. I can understand your situation and problem. Blood in sputum is known as hemoptysis. And it is seen in following conditions. 1.  Pneumonia 2. Tuberculosis 3. Lung cancer 4. Chronic bronchitis. So better to consult pulmonologist and get done 1. Clinical examination of respiratory system. 2. Chest x ray 3. PFT (Pulmonary Function Test). Chest x ray is needed to rule out pneumonia, tuberculosis and lung cancer. PFT is needed to rule out bronchitis. If all are normal, then no need to worry for Pulmonary causes. Forceful (voluntary) coughing can also cause hemoptysis due to friction bleeding. So avoid this. </s>