Bad breadth or halitosis affects many of the people around the world. The reasons for bad breadth include accumulation of food particles where the bacteria acting on the food substances produce gases which contribute to bad breadth. The characteristic rotten egg smell can be a bit too hard to stand up to.
Tooth decay is also a cause for bad breadth. Bad breadth of the mouth is also caused by the drying of the mouth. Since the saliva contains anti-bacterial properties absence of saliva creates bad smell in the mouth. Diseases of the gum and other parts are also causes of bad breadth.
Dieting and other starvation are found to increase bad breadth as acid deposits increase in the stomach creating foul smell. One major reason of bad breadth is smoking as it causes accumulation of tar and nicotine. Other major causes of bad breadth are infection of the intestine, kidneys etc which are non oral sources.