Mouthwash leads to bad breath, increases the risk of developing oral cancer, and causes staining of teeth and an uncomfortable stinging sensation in the mouth, states Daily Mail. This is because of some of its ingredients, such as alcohol. Alcohol breaks down the mucus-like coating that keeps the mouth moist.
Mouthwash contains a chemical called chlorhexidine gluconate. This chemical causes tooth staining within about 10 days of usage because it reacts with food additives, such as tannins -- present in coca cola, tea, coffee and red wine -- that remain on the teeth, reports Daily Mail.
Studies show that mouthwash counters the effect of toothpaste. Sodium lauryl sulphate, the foaming agent in toothpaste neutralizes fluoride in the mouthwash. The remedy for this is to wait for at least half an hour after brushing before sluicing with mouthwash, according to Daily Mail.
A study published in the Dental Journal of Australia in 2009 links mouthwash containing alcohol to a heightened risk of developing oral cancer, reports Daily Mail. The study reported that the ethanol in mouthwash permits cancer-causing substances, such as nicotine, to permeate the lining of the mouth more easily; however, the British Dental Health Foundation denies any link between oral cancer and alcohol in mouthwash.