There are a number of causes of bad breath. Food that you eat can affect the air you exhale. There are foods such as garlic and onions which are absorbed into the blood stream, broken down, transferred to the lungs and exhaled. Alcohol is another example. T he resultant odour is only temporally masked by brushing and mouth rinses and will remain until the body has completely digested the food. Individuals on a diet may also suffer bad breath due to a change in their digestion from irregular eating.