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Am Fam Physician. 2015;92(11):974-975

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Clinical Question

Does chewing gum reduce the risk of ileus by speeding the return of flatus and bowel movements in the postoperative setting?

Evidence-Based Answer

Having patients chew gum reduces the time to first flatus and time to first bowel movement, as well as the length of hospitalization by about half a day. (Strength of Recommendation: A, based on consistent, good-quality patient-oriented evidence.)

Practice Pointers

Postoperative ileus is common and may lead to prolonged hospitalization among other complications. Enhanced Recovery After Surgery techniques, including optimal pain control by epidural and local anesthesia, minimally invasive techniques, and aggressive postoperative rehabilitation, have been shown to reduce the risk of ileus.1 However, early postoperative feeding, one aspect of the Enhanced Recovery After Surgery program, may increase the risk of vomiting. Having patients chew gum in the postoperative period is not an aspect of the program, but it may decrease the risk of ileus by stimulating the cephalovagal system and intestinal motility while encouraging the flow of pancreatic juices and saliva.

This Cochrane review included 81 randomized controlled trials with 9,072 participants. Placebo interventions were sucking hard candy and wearing a silicone-adhesive patch or an acupressure wrist bracelet. Alternative treatments included early ambulation and sphincter exercises, stomach massage, chewing green tea leaves, early oral feeding, laxative use or early feeding, combinations of early oral hydration and early mobilization, or combinations of olive oil and water. Surgical procedures were categorized into colorectal surgery, cesarean delivery, and all other procedures.

The two outcomes used to signify that patients were recovering appropriately were time to first flatus and time to first bowel movement. Among all patients, the use of chewing gum reduced time to first flatus by 10.4 hours (95% confidence interval [CI], 8.9 to 11.9) and time to first bowel movement by 12.7 hours (95% CI, 10.9 to 14.5). Although outcomes favored chewing gum among all three groups of surgical patients, the effect size for both outcomes was greatest for patients recovering from colorectal surgery (time to first flatus reduced by 12.5 hours; time to first bowel movement reduced by 18.1 hours) and was smallest for those recovering from cesarean delivery (time to first flatus reduced by 7.9 hours; time to first bowel movement reduced by 9.1 hours).

Among all patients who used chewing gum, the length of hospital stay was reduced by 0.7 days (95% CI, 0.5 to 0.8). This effect was present across each of the three classes of surgical patients. Again, the effect was greatest in those undergoing colorectal surgery (reduced hospitalization by 1.0 day [95% CI, 0.4 to 1.6]) and smaller among those undergoing cesarean delivery (reduced hospitalization by 0.2 days [95% CI, 0.1 to 0.3]). Chewing gum was generally well tolerated and is inexpensive. Some studies reported less nausea and vomiting among those using chewing gum.

It is impossible to blind participants to this type of intervention, and most studies did not mask outcome assessment. However, risk of bias did not predict the extent of effect size on any outcome. Only four studies included patients who were otherwise being treated with Enhanced Recovery After Surgery techniques. In these participants, the effect size was smaller for time to first flatus, larger for time to first bowel movement, and there was no difference in length of hospitalization. Only four studies in this review included children.

Guidelines discussing care of patients after cesarean delivery do not specify most components of Enhanced Recovery After Surgery, nor the use of chewing gum.2 Guidelines regarding perioperative care of specific patient groups do include some aspects of the Enhanced Recovery After Surgery system, such as early feeding, but they do not discuss the use of chewing gum.3

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at

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