Chewing Gum Reduces Postoperative Ileus Following Abdominal Surgery

A Meta-analysis of 17 Randomized Controlled Trials

Shan Li; Yanqiong Liu; Qiliu Peng; Li Xie; Jian Wang; Xue Qin


J Gastroenterol Hepatol. 2013;28(7):1122-1132. 

In This Article

Abstract and Introduction


Background and Aim Chewing gum proposal has been used in surgery to reduce postoperative ileus for more than 10 years; however, the efficacy remains imprecise. The aim of this study was to accurately assess whether the use of the chewing gum could reduce duration of postoperative ileus following the abdominal surgery.

Methods A systematic review was conducted in Medline, EMBASE, and the Cochrane Library through December 2012 to identify randomized controlled trials comparing with and without the use of chewing gum in patients undergoing abdominal surgery. The outcome of interest was time to flatus, time to bowel movement, and length of stay. Subgroup analyses were performed to examine the impact of different studies structural design. Cumulative meta-analyses were used to examine how the evidence has changed over time.

Results Seventeen randomized controlled trials involving 1374 participants were included. Overall time (in days) for the patients to pass flatus (weighted mean difference [WMD], ™0.31; 95% confidence interval [CI], ™0.43 to ™0.19; P = 0.000); time to bowel movement (WMD, ™0.51; 95% CI, ™0.73 to ™0.29; P = 0.000); and length of stay (WMD, ™0.72; 95% CI, ™1.02 to ™0.43; P = 0.000) were significantly reduced in the treatment group. However, both of these results demonstrated significant heterogeneity. No evidence of publication bias was observed. Cumulative meta-analysis showed that chewing gum reduces duration of postoperative ileus that has been available for over 6 years.

Conclusions Results of the meta-analysis suggest that chewing gum following abdominal surgery offers benefits in reducing the time of postoperative ileus.


Postoperative ileus (POI) has been considered a temporary disturbance in gastric aVermeulen et al.[9] suggestednd bowel motility following abdominal surgery.[1,2] Almost all patients develop POI after abdominal surgery.[3,4] It is characterized by a transient cessation of bowel function, lack of bowel sounds, accumulation of gastrointestinal gas and fluid, pain and abdominal distention, nausea, vomiting, and delayed passage of flatus and stool.[1,2,5] The traditional end point of POI is the passage of flatus or a bowel movement. In general, operations that involve large incisions, extensive manipulation of the intestines, or exposure of the peritoneum to irritants such as blood or pus are more likely to result in POI.[1] The contributing factors of POI are varied, including pharmacologic, inflammatory, hormones, metabolic, gastrointestinal physiology, neurologic, psychological, and miscellaneous.[1] POI may extend length of hospital stay (LOS) 5 days longer than those without POI[6] and increase the expenditure of care by as much as between $750 million and $1 billion in the United States.[4,6,7] Safely shortening LOS and reducing the duration of POI are associated with improvement in the level of care provided as well as a significantly economic saving.

In order to reduce the duration of POI, various tactics such as a less invasive surgical procedure (e.g. laparoscopy), epidural anesthesia, early ambulation, nasogastric tube decompression, and early oral intake have been used in clinical setting.[8] But these methods should be have limited effect because the high incidences of POI have not been absolutely solved. Moreover, a meta-analysis by Vermeulen et al.[9] suggested that routine nasogastric tube placement serves no benefit on gastrointestinal functions and may even be harmful in patients after modern abdominal surgery.[9] Also, it is uncomfortable. A new approach that emphasizes patient comfort and based on available evidence should be considered. Sham feeding has been reported to stimulate bowel motility in humans.[10,11] Chewing gum is a type of sham feeding that simulates food ingestion. The reduction duration of POI afforded by chewing gum is supported by several studies.[12–25] However, other studies have obtained null results.[26–32] These discrepant evidences leave uncertainty in the surgical field about the efficacy of chewing gum in reducing the duration of POI. Several meta-analyses[33–37] showed a favorable effect of gum chewing on time to flatus and defecation, but all of these studies were small number size(less than 9 trials) and the results were not robust. Accordingly, we performed a systematic meta-analysis of randomized controlled trials (RCTs) to critically evaluate whether chewing gum reduces the duration of POI after abdominal surgery. If any, this may bring in providing an inexpensive, well-tolerated, and widely available solution to ameliorate an old problem.