You can also get the appearance of a black tongue if you use a chlorhexidine mouthwash (these are often uses to treatmouth ulcersor other mouth infections) or the medicine type antacid that has bismuth. If you
It depends on the mouthwash you are using. There are many over the counter alcohol based mouthwash’s that I feel can affect your health if used frequently in a negative fashion. Right off the bat if I mouthwash has alcohol in it this has been shown to be a carcinogen in many studies...