Exposure to chronic hypoxic conditions causes various gastric diseases, including gastric ulcers. It has been suggested that gastric smooth muscle contraction is associated with aerobic metabolism. However, there are no reports on the association between gastric smooth muscle contraction and aerobic metabolism, and we have investigated this association in the present study. High K+ - and carbachol (CCh-induced muscle contractions involved increasing O2 consumption. Aeration with N2 (hypoxia and NaCN significantly decreased high K+ - and CCh-induced muscle contraction and O2 consumption. In addition, hypoxia and NaCN significantly decreased creatine phosphate (PCr contents in the presence of high K+. Moreover, decrease in CCh-induced contraction and O2 consumption was greater than that of high K+. Our results suggest that hypoxia and NaCN inhibit high K+ - and CCh-induced contractions in gastric fundus smooth muscles by decreasing O2 consumption and intracellular PCr content. However, the inhibition of CCh-induced muscle contraction was greater than that of high K+ -induced muscle contraction.