As the first stop in the digestive journey, the mouth gets exposed to bacteria from whatever you consume. This bacteria settles on and in between the teeth, gums, and of course, tongue.
You may see this bacteria by sticking out your tongue as you look into a mirror. It often appears as a white coating or white spots, but it can also appear yellow or brown. According to the Mayo Clinic, this coating develops when the fingerlike projections (papillae) on the surface of your tongue become enlarged. When this happens, debris, bacteria, and dead cells can get stuck between them.
The goal of tongue scraping is to remove harmful bacteria that inflames your gums and causes cavities and bad breath, per the Cleveland Clinic.
That said, ayurvedic practitioners explain tongue scraping in a slightly different way: “When you have a coating on your tongue, that shows that your digestive system didn’t fully assimilate nutrients as well as it could,” Haasl-Blilie says.
That coating may contain some toxins (called ama in ayurveda) that were formed as your body processed the foods ingested, explains the Kripalu Center for Yoga and Health. According to ayurvedic tradition, scraping off that coating every day prevents those toxins from getting reabsorbed into your digestive tract, where they may weaken digestion and cause constipation, bloating, and other complaints, per Vedic Health.
However, it’s important to note that tongue scraping can’t entirely replace good oral hygiene habits. “The fundamentals of cleaning in between your teeth once a day, brushing twice a day for two minutes with a fluoride toothpaste, and seeing your dentist regularly are priceless,” says Alice Boghosian, DDS, a dentist in private practice in Park Ridge, Illinois, and spokesperson for the American Dental Association. “If you want to add in tongue scraping, that’s great, but it can’t take the place of these basics.”
https://www.everydayhealth.com/wellness/what-is-tongue-scraping/guide/