<s>[INST] Hi, When I brush my teeth and spit there is usually brown stuff in my spit and it doesnt feel like i have clean my teeth properly. Also I can feel some distasteful stuff in one location of my tooth, its always there and i go to brush that area and more brown stuff appears. what is this brown stuff? and how can i permanently remove it? [/INST] Hello, Everyone builds up daily plaque that you should remove with good dental hygiene. Your diet, health, habits and medications contribute to the composition. Smoking, coffee and tea are examples of stain causing culprits. If you are not effective in getting your teeth clean, consider a professional cleaning. Consider changing dental product choices. Have a complete dental exam. I suspect a tooth with decay and the hole builds up with debris. Some bacteria can cause discoloration on your teeth as well. Your dentist can check for this and any oral infections present. Have you had a recent dental check up? Think of any recent changes that you can attribute to the timing of the build up. A Chat Doctor. Thank you for your inquiry. </s>