mechanism underlying the anti-ulcer effects of plaunotol includes the increase of prostaglandin production in gastric mucosa (Ushiyama et al., 1987). On the other hand, Shiratori et al. reported that plaunotol released endogenous secretin, and that secretin is a potential mediator of the anti-ulcer actions of mucosal protective agents. Furthermore, they demonstrated that endogenous prostaglandin have a significant role in the inhibitory action of exogenous and plaunotol-released endogenous secretin in rats (Shiratori et al., 1993). In animal experiments, plaunotol prevents indomethacin-induced gastric mucosal injury by inhibiting neutrophil activation (Murakami et al., 1999). Thus, plaunotol prevents gastric mucosal injury and has gastroprotective actions through various mucosal defensive factors.