@deirdreanne I assume as part of the bronchoscopy that sputum samples were done. For myself, new hemoptysis would raise concern for infection. It’s also possible that your Bronchiectasis is progressing, as it does, and the pulmonary strain from running is causing one or more newly damaged/inflammed blood vessels to bleed. I agree with Sue, if no signs of infection and no other changes in your routines, I would at least trial stopping the NAC. AI says NAC is not generally associated with increased hemoptysis, but I feel like I have seen comments from fellow patients saying they couldn’t tolerate NAC as they felt it was causing them hemoptysis. Hopefully if I am right about that others will chime in. You may want to search prior posts on NAC and see what you find.