Pain after Licorice or Sugar-Water Gargling in Patients Recovering from Oropharyngeal Surgery-A Randomized, Double-Blind Trial

Glycyrrhiza glabrata (licorice) is used in traditional medicine and herbal remedies and reduces sore throats consequent to intubation, but whether it is protective for more intense pain after oropharyngeal surgery remains unclear. We thus tested the joint hypothesis that gargling with licorice, which has anti-inflammatory and antioxidant properties, reduces postoperative pain and morphine consumption. We enrolled patients having elective oropharyngeal surgery. Participants were randomly allocated to gargle with either 1 g licorice or a sugar placebo before and for up to three days after surgery. A numerical rating scale (NRS) for pain along with morphine consumption was evaluated every 30 min during the post-anesthesia care unit (PACU) stay and then three times daily for three days. We pre-specified that licorice gargling would be deemed better than sugar gargling only if found non-inferior on both morphine consumption and pain score and superior on at least one of the two. 65 patients were randomized to the licorice group and 61 to placebo. We found noninferiority (NI) in pain scores with an estimated mean difference of -0.09 (95.2% CI: -0.88, 0.70; = 0.001; NI delta = 1) between licorice and placebo gargling. There were no adverse events reported in either group that required treatment discontinuation. Gargling with licorice did not significantly or meaningfully reduce postoperative pain or morphine consumption in patients recovering from oropharyngeal surgery. While higher doses might prove more effective, our results suggest that other topical analgesics should be considered.