['To investigate effects of perirenal space blocking (PSB) on gastrointestinal function in patients with severe acute pancreatitis (SAP).', 'Forty patients with SAP were randomly allocated to receive PSB or no PSB (NPSB). All the SAP patients received specialized medical therapy (SMT). Patients in the PSB group received PSB + SMT when hospitalized and after diagnosis, whereas patients in the NPSB group only received SMT. A modiﬁed gastrointestinal failure (GIF) scoring system was used to assess the gastrointestinal function in SAP patients after admission. Pain severity (visual analog scale, 0 to 100) was monitored every 24 h for 72 h.', 'Modified GIF score decreased in both groups during the 10-d study period. The median score decrease was initially significantly greater in the PSB group than in the NPSB group after PSB was performed. During the 72-h study period, pain intensity decreased in both groups. The median pain decrease was significantly greater in the PSB group than in the NPSB group at single time points. Patients in the PSB group had significantly lower incidences of hospital mortality, multiple organ dysfunction syndrome, systemic inflammatory response syndrome, and pancreatic infection, and stayed in the intensive care unit for a shorter duration. However, no difference in terms of operation incidence was found between the two groups.'] Does perirenal space blocking restore gastrointestinal function in patients with severe acute pancreatitis?