Dear Doctor, A friend of mine has really bad breath and I find it hard to have a conversation with them. I have offered gum in some cases but I think she will one day suspect that I’m trying to tell her something. In the event that I’m bold enough to tell her, can you please let me know what advice I can give her? I’ve seen her brush her teeth so I know that is not the problem. Please help. Stacey Dear Stacey Dr Rachna Pande I appreciate your concern for your friend and your sensitivity in not wanting to hurt her. Bad breath or halitosis is said to be one of the most common causes for people seeking consultation with dentists. The problem may be transient, for example, it may improve after cleaning the mouth or with some medications or it may be chronic. The problem of bad breath occurs mostly in mornings. This happens because the mouth remains closed during the night thus not being exposed to oxygen and also, it retained food particles putrefy due to bacterial action. In 90 per cent cases, the cause for bad breath rests in the mouth. Poor oral hygiene is one of the most common causes. Trapped food in between the teeth or gums causes bacteria to grow. This leads to putrefaction and bad breath. Mostly, these chronic infections occur at the base of the tongue, in between the teeth or at the root of teeth. Gaps in between the teeth, broken teeth, prosthesis, poorly aligned dental crowns, etcetera; make the teeth more vulnerable to such infections. Those suffering from immune depressed conditions like diabetes have a higher risk of developing oral infections. In fact foul smelling breath is often the first sign of diabetes. Apart from bacterial infections, other infections of the oral cavity like viral or fungal also impart bad smell to the breath. These infections are curable by use of antiseptic mouth wash and suitable antibiotics. Once cured, good oral hygiene prevents further recurrence of bad breath. Dryness of the mouth also tends to increase the risk of oral infections. Hence drinking a lot of water prevents dryness and this risk of infection. It is not only important to clean the teeth, but to clean them in a proper way. This involves cleaning from up to down, both in front and behind. Tooth brush should not be hard. A dentist or dental technician can demonstrate the correct technique of brushing. For being efficient, a tooth brush should be changed when the bristles start to wear out, like in a month. Use of dental floss is said to be very useful in good cleaning of teeth. Certain foods like onions, garlic, among others, tend to impart a bad smell to the breath. One consuming these kinds of food should rinse the mouth very well and brush thoroughly after eating. One can have a foul smelling breath due to chronic infections of the nose and or throat as well. Smokers tend to have a malodorous breath. Diseases like that of the liver and uncontrolled diabetes cause foul smelling breath. But here, there would be overlapping predominant features of the systemic disease. It is advisable for your friend to consult a dentist and follow his advice. It would be prudent to check for diabetes as well.Dr. Rachna is a specialist in internal medicine at Ruhengeri Hospital.