text: In a 2022 observational study aimed to identify preoperative serum metabolites that could predict postoperative opioid consumption, the role of imidazole-4-acetaldehyde was identified as one of the metabolites that showed different trends between gastric cancer patients with high postoperative opioid consumption and those with low opioid consumption group. The results suggest that imidazole-4-acetaldehyde, along with other metabolites, was significantly different between the two groups, so that that imidazole-4-acetaldehyde may serve as a potential biomarker for predicting postoperative opioid consumption in gastric cancer patients, still, the results of this study is inconclusive.