Is it true that if u take a teaspoon of vinegar a day it would bring your blood pressure down?

Apple cider vinegar. There are no good human studies to suggest apple cider vinegar is a useful treatment for bp. There was one done in rats which suggest it could help - but what that means for humans is unclear. On scale of 1-10 in terms of usefulness, i'd give it a 2.... If you wanted to try it, why not... It's cheap and won't kill you. But it's no substitute for the proven things: low salt, exercise.