Dear Doctor, I buy and use mouthwash from time to time, mostly to keep my breath fresh. Are there any other advantages? Do they help in maintaining oral health? And how often should I use them? Adam -- Dear Adam, Mouthwash is a liquid used to rinse the teeth, gums and tongue, i.e. all contents inside the oral cavity. It contains antibiotics to check infection, compounds like zinc, ketone to prevent bad odour, essential oils, analgesic, fluoride, alcohol, hydrogen peroxide and other ingredients in variable amounts. Dentists usually recommend use of mouth wash to heal an empty socket after tooth extraction, treating bad mouth odour, bacterial plaques formed around teeth and gums, inflammation of gums and around teeth, preventing or treating tooth decay, dental caries, whitening of teeth, treating oral sores, dryness of mouth, and so many conditions of the oral cavity. One is supposed to rinse the mouth with mouthwash after thoroughly brushing/flossing the teeth. It is poured from a small cup in the mouth, swish it around thoroughly for half to one minute and then spit in the sink. It should not be diluted with water, as that reduces its efficacy. One should avoid eating, drinking or smoking for at least 30 minutes after using mouth wash, so that its effect is not diluted. It is effective in reducing pain and inflammation of teeth and or gums, treating dental caries, preventing or reducing bad odour from mouth, preventing tooth decay and cavities, and healing oral sores. As for most of the medicinal products, results of use of mouthwash become evident after consistent use for some days. But it is not a substitute for good cleaning and flossing of the teeth. Along with killing harmful bacteria, it also destroys useful bacteria present in the oral cavity, thus reducing the ability of inner lining of mouth to fight dental and gum infections and bad breath. Alcohol or menthol containing mouth washes can cause burning sensation in mouth after use. Alcohol present in mouth wash can destroy inner protective layer of the oral cavity. This increases vulnerability to acquire infections and also increases sensitivity of gums to hot or cold things. There is a raging debate going over, whether alcohol present in mouth wash can cause cancer? Many commercially available mouth washes have high acid levels that can destroy the dental enamel overtime, thus causing discolouration. Regular use of hydrogen per oxide containing mouth wash can also damage tooth enamel. It is not necessary to use a mouth wash daily just for cleaning the mouth and maintaining fresh breath. Regular adequate cleaning, rinsing mouth with salt water is also effective for same purpose. However, if there is any need for it, it should not be used in excess. Just using it twice, morning and evening, is good enough. Dr. Rachna Pande is a specialist internal medicine.