Can apple cider vinegar reduces swelling under eyes?

No: There is no evidence that any vinegar product will reduce swelling.

Careful!!!: Wow. This is the second time i've heard somebody using that. However, the first time i've seen somebody use it, they got some of it in the eye and caused a chemical burn on their cornea which required a long painful recovery. There is no evidence that it helps, but I have seen it become very dangerous! i would not suggest it.