Based on recent research, mouthwash is now in question in my books.
We aimed to assess if daily usage of Listerine Cool Mint influenced the composition of the pharyngeal microbiome… Listerine use was associated with an increased abundance of common oral opportunistic bacteria previously reported to be enriched in periodontal diseases, oesophageal and colorectal cancer, and systemic diseases. These findings suggest that the regular use of Listerine mouthwash should be carefully considered.
Basically, it differentially kills good bacteria, leaving more of the bad kind.