While working in the nursing homes and hospitals, alot of people ask me about salt substitutes for lowering blood pressure. While these substitutes may work great for some, they are not appropriate for others. Most salt substitutes replace sodium (the Na in NaCl) with potassium (making KCl). While this is not a problem for alot of people, individuals with kidney problems could be hurt by taking in too much potassium.
Bottom line, check with your doctor or dietitian before starting salt substitutes, especially if you have kidney problems or are currently being treated for other health problems.
Tips from the American Dietetic Association