Coughing up thick brown stuff when I brush my teeth?

Need more info. Coughing up thick brown stuff when brushing your teeth may or may not indicate a problem. If you brush your teeth after snacking or drinking, what you are coughing up may be a residue from either the drink or snack you recently consumed. If you are in good health, this may or may not indicate a problem. However, if this continues, a medical consultation may be indicated.
Unusual. Do you cough up the same material at other times? How long has this been going on? Are you suffering from any other symptoms; ear ache, sore throat, sinusitis, watery eyes? If so, you may have a bacterial infection of some sort and should see your pcp. If not, it may be as simple as drinking coffee or tea, which will stain your mucus a tan/brown color.