evidence: If you already have high blood pressure, too much salt will raise it further, and may mean that any blood pressure medicines you’re taking don't work as well as they should. Cutting down on salt is one of the simplest ways to lower your blood pressure, and will start to make a difference very quickly, even within weeks. [...] Salt is made up of sodium and chloride, and it’s the sodium that raises blood pressure. 1g of sodium is the same as 2.5g of salt.