Capsaicin, the main ingredient in hot chili peppers, elicits a sensation of burning pain by selectively activating sensory neurons that convey information about noxious stimuli to the central nervous system. The capsaicin receptor, transient receptor potential vanilloid 1 (TRPV1), is predicted to have six transmembrane (TM) domains and a short, pore-forming hydrophobic stretch between the fifth and sixth TM domains, and is activated not only by capsaicin but also by heat (>43 degrees C), acid and various lipids. Within the TPRV1 protein, many regions and amino acids involved in specific functions (multimerization, capsaicin action, proton action, heat activation, desensitization, permeability, phosphorylation and modulation by lipids) have been identified since the cloning in 1997. Given the fact that TRPV1 is a key molecule in peripheral nociception, these regions and amino acids could prove useful for the development of novel anti-nociceptive or anti-inflammatory agents.