Changes in portal pressure before and after hepatic resection were monitored in 65 patients. Significant increases in portal pressure, from 226 +/- 13 mm saline to 277 +/- 16 mm saline were noted in 17 cirrhotics undergoing major hepatic resection. In 14 noncirrhotics undergoing major resection of the liver, pressure in the portal vein changed significantly from 198 +/- 10 mm saline to 226 +/- 9 mm saline. Conversely, there were no differences in the 26 cirrhotic and eight noncirrhotic individuals who underwent minor hepatic resection. Clinical analysis of these patients showed that acute portal hypertension induced by liver resection was not linked to increases in early postoperative death.