Capsaicin and Menthol Patch is used to relieve muscle/joint aches. What Capsaicin basically does is that it decreases a natural substance (substance P), which in turn helps pass pain signals to the brain. Menthol, on the other hand, makes the skin feel cool and then warm. Of course, this cooling and refreshing sensation on our skin distracts us from feeling the aches deeper in our muscles and joints. However, in some cases, taking the capsaicin/menthol patch off is recommended if you start feeling a very bad burning or itching. It is also recommended that you tell your doctor if you are pregnant or breastfeeding to learn from them if you should/should not use Capsaicin and Menthol Patch. Apart from the usual allergic reactions that can happen (namely rash, hives, itching, and trouble breathing), this patch can also cause skin irritation and stinging feeling, which in turn will go away after a couple of days.