Dear Doctor, I am having a problem relating to my sputum , mostly in the morning, it is dark brownish, off late I also have a sore throat . I am living in xxxxxx, this problem started probably in Mar-2012, still not solved. I went to docs here, they tested for TB, it was negative. Tested for aerobic and anaerobic, it is also negative. Not sure what the problem is, I am worried. also for your information, I am diabetic since Sep-2006, this is just for information.