In 20 controls and 60 patients who underwent partial gastrectomy or vagotomy respectively the bilirubin-contents of the gastric juice was traced and related to pH, intragastric pressure and bacterial contamination. A reflux of bilirubin could be ensured in 70% of the controls. Low bilirubin values could be found in the control group and after selective proximal vagotomy without pyloroplasty; higher values after SPV with pyloroplasty according to Finney, antecolic B-II-resection with ileo-ileostomy and in B-I-resection. Maximal values could be found after retro- and antecolic B-II-resection without ileo-ileostomy. There was a close correlation of these values to bacterial contamination and pH-value, but no correlation existed to the intragastric pressure.