I agree with @bee1950. I've coughed up about 2-3 TBS blood twice over the past 4 years (a combination of red blood and clots). The first time, I went to the ER and that, eventually, led (after about 1 ½ yrs) to the diagnosis of bronchiectasis and MAC. I cough in the mornings, but don’t really have any other symptoms and don’t take any antibiotics. I exercise/walk 2-3 miles daily and nebulize 7% saline. I've been investigating whether coughing up blood may actually be a good thing in MAC. In my reading of MAC articles, I found one called "Retrospective study of the predictors of mortality and radiographic deterioration in 782 patients with nodular/brochiectatic MAC lung disease" by Gochi et al. ( https://www.ncbi.nlm.nih.gov/pubmed/26246077 ) From the article, very few people seemed to die of MAC-related issues. The women with bloody sputum fared the best. I'm trying to find out why.