Yes drinking a bit of white vinegar can lower your blood pressure when it's high and in fact white vinegar and vinegar has been used medicinally for thousands of years to treat high blood pressure and other conditions.
Vinegar is a natural way of lowering your blood pressure and it does work but if you want to have a better taste I would recommend taking a tablespoon or two of apple cider vinegar since it tastes better than plain vinegar does and it too helps lower your blood pressure levels.
You can take up to 3 tablespoons of apple cider vinegar or the plain white vinegar per day and you should see a decrease in blood pressure overnight.
Vinegar and apple cider vinegar also helps with indigestion as well.