I'm not sure how it works but I discovered Epsom salt is great for blisters on my feet. After wearing a pair of ill fitting shoes I had blisters on both heels and my little toe. Of course, my feet ached too so I thought I'd try soaking them in the Epsom salt. I used about 1 cup in a basin of warm water and soaked for about 10 minutes. It not only helped my aching feet but the next morning my blisters were nearly gone!