<s>[INST] My husband has mothball breath. Any idea what we can do to prevent this? He is 30 years old and in good health (to our knowledge). I was wondering if dairy foods could cause this since that is the one food he seems to have a reaction to (mild bloating, etc. - doesn't seem to be complete lactose intollerance).  He flosses and brushes regularly and we have used several mouthwashes. [/INST] Hello,Gastric disturbances can cause bad breath in some instances. Lactose intolerance is not particularly assocoated with bad breath. Acid reflux can cause an acid feeling in the mouth and change the oral environment. Medications can cause dry mouth. Dehydration and breathing through your mouth can irritate oral tissue. Plaque becomes more difficult to remove. Be sure to brush the tongue as a coating on the tongue can create an odor. Tonsil stones, located in back of the throat, are another possibility. Sinus congestion with post nasal drip can contribute as well.The most likely cause and first area of evaluation should be your oral health. A routine dental exam will rule out active areas of decay, abscess and periodontal conditions that need to be addressed. Evaluation of your oral hygiene and instruction on proper oral care will include an evaluation for bad breath. Some additional basic techniques may be recommended. The most typical cause of persistant bad breath is buildup of bacteria in the mouth. First rule this out. A thorough cleaning is needed and tartar removed. Even with daily home care, there may be tartar undeer the gums if you have not had a recent dental cleaning.Diet and chemicals can contribute to bad breath. Once in the blood stream, with blood traveling to the lungs, your breath can be effected. The smell of garlic, spicy foods and alcoholic can be obvious on the breath of people who have recently consumed these. This type of bad breath is temporary and easily controlled with a diet change. Avoid certain foods if you suspect this to be the cause. Smoking and the body breaking down medications including vitamins may contribute. Make your diet is balanced. Deficiencies or excess viamins and minerals should be avoided. Keep well hydrated for your entire body systems to function properly.Even a dietary change or fasting can cause an unhealthy sweet breath. This can be due to chemicals called ketones being expelled. They are made by the breakdown of fat. Diabetes can be suspected with this symptom and may warrent further evaluation by your physician.A fishy type odor, from the syndrome trimethylaminuria, is possible due to the inability to properly break down trimethylamine which is found in certain foods. There may be a build-up of trimethylamine in the body which can be released in your breath. Urine and blood tests are suggested help to confirm this diagnosis if it is suspected. This may be noticed in sweat and urine as well. This is not a common condition.I thank you for your inquiry and hope you find my suggestions helpful to assist you with an answer and solution. </s>