Bad saliva is generally caused by oral problems, on the one hand, because there are periodontal diseases such as gingivitis, periodontitis and other pus inflammatory substances caused. On the other hand is poor oral hygiene, the breeding and reproduction of bacteria will make the saliva bitter and salty, bacteria make the fermentation of food left in the mouth, will also make the saliva smelly. Bad breath is mainly caused by stomach fire, the spleen and stomach and abnormal digestive function, food in the stomach can not be digested in time will emit a putrid smell, from the mouth to form bad breath. Whether it is bad breath or bad breath, you need to maintain good oral hygiene, brushing is the most basic and necessary a way to brush your teeth in time after meals, but also the use of dental floss, do not let the mouth have food residue and soft dirt. If necessary, you can use mouthwash, mouthwash with bactericidal effect do not use for a long time, inflammation can stop after removal, periodontal disease or stomach disease to be treated in a timely manner.