I've never heard of TCP, I don't think it's marketed in the US at all.

It's a traditional antiseptic introduced in the UK in the 1920s. It has a strong, somewhat medicinal, smell. I gargled it once, and regretted it because it tastes foul.

http://www.capetalk.co.za/articles/303079/new-antiseptic-tcp...

https://www.wilko.com/en-uk/tcp-antiseptic-liquid-200ml/p/02...

Ah, that's how you know it must work. The worst tasting a medicine is, the better it must be for you. Stands to reason.

It is effective against gingivitis and mouth ulcers and will also ward off vampires and werewolves. Actually smells better than garlic and is cheaper than silver, so win win.

It really isn't that bad to gargle but not particularly pleasant either. It is effective though and that's the real point.