Halitosis or bad breath – this is common and may be persistent or recurrent.  While the usual factors include gum disease, rhinitis, laryngitis, chronic tonsillitis and some tumours in the pharynx and commonly the cause is not due to acid reflux. Analysis of the gases that cause halitosis show that they are volatile sulphides which can arise either from the mouth or the colon. When produced in the colon these gases are reabsorbed and expired on the breath.  Some sulphur gases that originate in the mouth disappear shortly after teeth cleansing only to return over the next hour.  In contrast other gases which originate in the gut are largely unaffected by brushing of the teeth. Garlic is a good example of the cause of bad breath with early bad breath being due to garlic in the stomach but garlic breath in the morning is due to gases generated from the colon.