Hot peppers or other spicy foods cause ulcers, but there's no evidence that they do. Studies of areas where hot peppers are used extensively in cooking, such as Brazil and Thailand, have found no higher incidence of stomach ulcers among their populations. And in a study conducted at a Veterans Administration hospital, researchers ground up about anounce of jalapeno pepper and injected it directly into the stomachs of volunteers. Follow-up observation showed no damage to their stomach linings. Neither do hot peppers aggravate or cause hemorrhoids as has often been claimed, since capsaicinoids, the hot substance, are broken down before they reach the lower intestine.

Chili peppers contain a substance called capsaicin, which gives peppers their characteristic pungence, producing mild to intense spice when eaten. Capsaicin is a potent inhibitor of substance P, a neuropeptide associated with inflammatory processes. The hotter the chili pepper, the more capsaicin it contains. The hottest varieties include habañero and Scotch bonnet peppers. Jalapeños are next in their heat and capsaicin content, followed by the milder varieties, including Spanish pimentos, and Anaheim and Hungarian cherry peppers.