If you notice a sudden onset of bad breath when there was no bad breath before, there are several reasons to consider. The first reason is the local appearance of dental calculus. Tartar is formed by the mineralization of bacteria over a long period of time, and is very bacterial in itself, which can also stimulate inflammation of the gum tissue and cause bad breath. The second reason is to eat food with irritating taste, such as leek, garlic, etc.. Generally apply mouthwash to rinse the mouth, after 2-3 days of time, bad breath will disappear. The third reason is that the esophageal digestive tract disease, such as reflux esophagitis, the smell of food decay in the digestive tract will be discharged through the mouth, halitosis.