Cayenne pepper is a hot red pepper used to flavor dishes; its name comes from the city of Cayenne in French Guiana. Its powdered form comes from the fruit of several cultivated varieties of the Capsicum baccatum and Capsicum frutescens very closely related to bell peppers, jalapeños, paprika, and others. All are related species of the nightshade family (Solanaceae).

The fruits are generally dried and ground, or pulped and baked into cakes, which are then ground and sifted to make the powder.

Cayenne is used in cooking spicy hot dishes, as a powder or in its whole form (such as in Szechuan cuisine). It is generally rated at 40,000 to 90,000 Scoville Units. It is also used as an herbal supplement, and was mentioned by Nicholas Culpeper in his Complete Herbal.

Historical or traditional use:
The potent, hot fruit of cayenne has been used as medicine for centuries. It was considered helpful for various conditions:

• Gastrointestinal tract: including stomachaches, cramping pains, and gas.
• Diseases of the Circulatory System. It is still traditionally used in herbal medicine as a circulatory tonic (a substance believed to improve circulation).
• Rheumatic and arthritic pains: Rubbed on the skin it causes, what is termed as, a counterirritant effect. A counterirritant is something which causes irritation to the area to which it is applied. This makes it distract the nerves from the original irritation (such as joint pain in the case of arthritis).

Active components:
Cayenne contains a resin-like pungent substance known as capsaicin. This chemical relieves pain and itching by affecting sensory nerves. Capsaicin temporarily causes various neurotransmitters to release from these nerves, leading to their depletion. Without the neurotransmitters, pain signals can no longer be sent. The effect is temporary. Capsaicin and other constituents in cayenne have been shown to have several other actions, including reducing platelet stickiness and acting as antioxidants.