Concentration of Cholecystokinin(CCK) and Somatostantin(SS) in Plasma, 24 h urine and morning urine were observed in 57 pilots (22-45 years, mean 27.9) and 60 ground crew (23-47 years, mean 30.7). The results showed that CCK level in plasma, 24 h urine and morning urine (20.14 +/- 4.15, 10.08 +/- 2.29 and 11.29 +/- 2.18 pmol/L respectively) in pilots were significantly lower than those in ground crew (22.89 +/- 3.76, 7.04 +/- 1.03, 8.10 +/- 1.94 pmol/ L respectively) and those of SS were distinctly higher than in ground crew (12.38 +/- 2.34, 6.75 +/- 1.18, 7.41 +/- 1.27pmol/L respectively). Concentration of CCK and SS in plasma were positively related to those in 24 h urine and morning urine both in pilots and ground crew. It suggests that these changes might play potential role in the pathogenesis of some diseases of digestive system in pilots.