Hello There are many underlying disorders that can cause hemoptysis (coughing up blood), ranging from heart problems to trauma to infections to lung disease. Worldwide, tuberculosis is the most common cause of hemoptysis. In industrialized countries, the most common causes are bronchitis, bronchiectasis, and bronchogenic carcinoma. In patients with AIDS, the most common cause of hemoptysis is pneumonia. In about 15% to 30% of cases, the underlying problem is never found—undiagnosed hemoptysis is commonly referred to as idiopathic hemoptysis. Haemoptysis may also be due to any of the followings Endobrochial lesions Arterio venous malformation High blood pressure Bleeding disorders For that check ur BP Consult a Pulmonologist and do following investigations BT, CT, APTT, PT CT Angiography to rule out any AV malfomations Fiberoptic Bronchoscopy to rule out any endobronchial lesions At last hemoptysis can be idiopathic without any cause. Discuss this with your doctor and then decide Hope this helps Take Care.