The purpose of this study was to reseach the relationship between the upper gastroin- testinal endoscopy and heart rare and blood oxygen saturation (SaO2 ) , 62 patients were examined by (esophagogastroduodenoscopy , EGD ) and monitored with a transcutaneous pulse oximeter simultane- ously. The mean age was 44. 5 years (range 21 - 68) , 30 males and 32 females. No sedative drugs and at- ropin were used. The mean pulse and SaO2 value before endoscopy were 94. 12/min and 97. 68%. During the ECD SaO2 was slightly decreased by a mean of 1 . 61% ( P 100/min accounted for 61 . 3%, it was more than preendoscopy (P