Cayenne pepper, or simply “red pepper” in its powdered form, is one of the most popular spices and a mainstay in the cuisine of much of Asia, as well as the American Southwest, Mexico, and Louisiana. It has also been a fixture of Chinese folk and Ayurvedic medicine. 

Perhaps the most famous special quality of cayenne, outside of its fiery taste, is its its ability to kill pain. Capsaicin is the pepper's active ingredient, and research has verified its pain relieving efficacy when taken orally or via injection. Applied topically, capsaicin is effective at relieving pain from osteoarthritis and other chronic pain, as well as reduce postsurgical neuropathic pain among cancer survivors. Capsaicin has also been shown to reduce the amount of substance P, a neuropeptide that carries pain messages to the brain. The less substance P in your system, the less pain you will feel. It's shown to be a particularly effective treatment for cluster headaches.

The capsaicin in cayenne pepper can also raise your core body temperature slightly. Why would you want that to happen?  Researchers at Purdue University discovered that such a state (called “thermogenesis”) results in you burning more calories. What's more, the same study also concluded that people who were not in the habit of eating spicy foods would experience an overall reduction in appetite if they consumed just 0.3 grams of cayenne pepper a day.

Your grandmother may have used cayenne pepper in one of her homebrew recipes for coughs, colds and congestion – and science now shows she was on to something. Indications are that capsaicin can relieve congestion by shrinking the blood vessels in the nose and throat.

Capsaicin can be a real boon to those who suffer from psoriasis. Topical application has been proven to significantly improve the itching an other symptoms associated with this skin disease.

There is one cayenne caveat, however: be sure to keep it away from any open wounds or sores, as it will be terrifically painful.