Some spicy foods have anti-cancer potential. Turmeric, a peppery-flavored spice native to India, contains the active antioxidant curcumin, which has shown some anti-cancer effects in lab studies. Though small studies have shown positive results, according to the Mayo Clinic, curcumin requires further investigation before being used for cancer treatment. The American Cancer Society suggests that capsaicin may help slow the growth of prostate cancer cells. Further studies on humans are needed and, thus, it is not recommended for treatment at this time.