ImportanceDespite the recovery advantages of minimally invasive surgical techniques, delayed return of gut function after colectomy is a common barrier to timely discharge from hospital.ObjectiveTo evaluate the effect of 2% perioperative intravenous lidocaine infusion on return of gut function after elective minimally invasive colon resection.Design, Setting, and ParticipantsThe ALLEGRO trial was a randomized, placebo-controlled, double-blind trial conducted in 27 UK hospitals. A total of 590 adults scheduled for elective minimally invasive colon resection for benign or malignant disease were randomized 1:1 to 2% intravenous lidocaine or saline placebo. Enrollment occurred from August 13, 2018, to April 11, 2023, with a pause in recruitment from March 20, 2020, through July 6, 2020; final follow-up was on August 10, 2023.InterventionsThe intervention patients received 2% intravenous lidocaine administered as 1.5-mg/kg bolus at induction of anesthesia followed by 1.5 mg/kg/h for 6 or 12 hours. Control patients received 0.9% saline placebo for 6 or 12 hours.Main Outcomes and MeasuresThe primary outcome was the proportion of patients with return of gut function at 72 hours after surgery, defined by the GI-3 composite end point of tolerating diet (ingestion of food and drink without significant nausea or vomiting for 3 consecutive meals) and passage of flatus or stool. There were 11 secondary outcomes, including time to GI-3 recovery, time to GI-2 recovery (tolerance of oral diet and passage of stool), prolonged postoperative ileus, postoperative nausea and vomiting score, Overall Benefit of Analgesia Score, postoperative opioid consumption, Quality of Recovery–15, quality of life (EuroQol 5-Dimension 5-Level), enhanced recovery protocol adherence, time to meeting medically defined criteria for discharge, and time to patient self-assessed readiness for discharge.ResultsThe trial enrolled 590 patients (295 intervention, 295 control); after 33 postrandomization exclusions, 557 patients were included (279 intervention, 278 control; 249 female patients [44.7%]; mean [SD] age, 66 [10.9] years); 532 (96%) received the randomized treatment. Return of gut function as defined by the GI-3 composite outcome was achieved at 72 hours by 160 patients (57.3%) in the intravenous lidocaine group vs 164 patients (59.0%) in the placebo group (adjusted absolute difference, −1.9% [95% CI, −8.0% to 4.2%]; relative risk, 0.97 [95% CI, 0.88 to 1.07]). There was no significant difference between the intervention and control groups in any of the 11 secondary end points.Conclusions and RelevanceAmong patients undergoing elective minimally invasive colon resection, perioperative administration of 2% intravenous lidocaine did not improve return of gut function at 72 hours.Trial Registrationisrctn.org Identifier: ISRCTN52352431