DowrgiI’d exercise caution and seek medical advice first. If I’m not mistaken, aspirin contains acetylsalicylic acid, not “pure” or “natural” salicin found in willow bark. Although I’ve read of different ways to use aspirin externally, I believe that both natural salicin and acetylsalicylic acid may also provoke reactions in some people’s skins and it certainly shouldn’t be used externally if someone is allergic/intolerant to normal use, asthmatics should be especially careful.