system
Given the following post, respond as if you're commenting on Reddit:
human
Is using mouthwash products such as Listerine actually beneficial to your gums? Are there any adverse effects?

I was googling this and there were a lot of articles arguing both ways, some saying that it kills the bad bacteria but also killing the good bacteria as well. 

Other articles were saying how it actually contributes to making bad breath even worse, also damaging your tooth enamel.
gpt
Dental student reporting in:  what I've been taught is that most mouthwashes don't do very much aside from making your breath smell nice.  One important exception is Peridex (chlorhexidine) which is the last resort stuff prescribed by dentists when patients really need to have better hygiene and nothing else is reliable.  Also, Peridex turns teeth brown.  Mouthwashes with fluoride have been shown to have some beneficial effects for remineralizing very small cavities (ACT brand has fluoride in it).  Alcohol containing mouthwashes are kinda iffy in that alcohol can contribute to oral cancer (alcohol works synergistically with smoke).  Specifically in terms of benefits for your gums: regular flossing, mild stimulation with a brush, and a cleaning every few months are more than adequate solutions to gum disease.

Sources: Mouthrinses for the treatment of halitosis
Zbys Fedorowicz, Hamad Aljufairi, Mona Nasser, Trent L Outhouse, Vinícius Pedrazzi
Editorial Group: Cochrane Oral Health Group

Fluoride mouthrinses for preventing dental caries in children and adolescents
Valeria CC Marinho, Julian PT Higgins, Stuart Logan, Aubrey Sheiham
Editorial Group: Cochrane Oral Health Group


Tl;dr: Mouthwash does not appear to really help your gums that much and alcohol containing mouthwashes like most types made by Listerine appear to have adverse effects.