Arguably, the only inconvenience related to mouthwash use is the sting. Some can’t stand the burning sensation whenever they wash their mouth with a generous helping. While no-sting formulas in the market exist, the burning sensation is often considered a sign of the mouthwash's effectiveness.
The dental community is divided as to what causes the burning sensation with every swish or gargle with the mouthwash. According to BreathMD.com, the alcohol content is to blame. This is the more common argument where some mouthwash brands contain up to 30 percent alcohol. As a desiccant, alcohol dries up the mouth, leaving it prone to the slightly bothersome sting.
However, Dr. Scott Frey, a U.S. dentist, disputes the alcohol argument, saying that the essential oils in the mouthwash cause the burning sensation more frequently than the alcohol content. These oils, Frey said, tend to irritate the walls around the oral cavity, causing the sting.
Who's telling the truth? Nobody knows. All they know is that the burning sensation is unlikely to go away anytime soon. Nevertheless, there's no reason to stop using them now, given that they've been helpful in keeping oral bacteria in check. As long as you use them according to the manufacturer's instructions, mouthwash—sting or no-sting—will do you no harm.