Background <p>Disulfiram-like reactions are associated with alcohol consumption during the administration of specific drugs, and their diagnosis is a challenge in clinical and forensic medicine. This study investigated the feasibility of acetaldehyde-protein adduct (APA) as an auxiliary diagnostic index of disulfiram-like reactions. To explore the feasibility of APA as an auxiliary diagnostic index of disulfiram-like reactions, adult male Sprague Dawley (SD) rats were randomly divided into 4 groups, with 8 rats in each group: Control group was given intravenous injection and oral normal saline, Cefoperazone group was given intravenous injection of cefoperazone and oral normal saline, Alcohol group was given intravenous injection of normal saline and oral ethanol, and Cefoperazone + Alcohol group was given intravenous injection of cefoperazone and oral alcohol. All rats were sacrificed 1&#xa0;h after the last gavage, and blood samples and liver tissues were obtained for subsequent detection. Furthermore, to explore the time-sequential change in APA in postmortem rats, hepatic APA was detected after the cadavers were stored at 25&#xa0;°C for 0&#xa0;h, 1 d, 3 d, 5 d and 7 d. In addition, to evaluate the specificity of APA in disulfiram-like reactions, another 8 SD rats were selected to set up an Acute alcoholism group and were given a lethal dose of ethanol orally, then the APA levels of rats in cefoperazone + alcohol group and Acute alcohol poisoning group were compared.</p> Result <p>The first part of the results revealed that compared with Control group and Alcohol group, hepatic acetaldehyde dehydrogenase (ALDH) activity was significantly decreased in both Cefoperazone group and Cefoperazone + Alcohol group (<i>P</i> &lt; <i>0.0001</i>). Conversely, the levels of APA in both blood and liver were significantly higher in Cefoperazone + Alcohol group than in Control group, Cefoperazone group and Alcohol group (<i>P</i> &lt; <i>0.05</i>). The second part of results showed that there was no significant difference in hepatic APA levels between each adjacent time point in each group (<i>P</i> &gt; <i>0.05</i>), except in Cefoperazone + Alcohol group, where the APA in the liver significantly decreased from 0&#xa0;h to 1&#xa0;day after death (<i>P</i> &lt; <i>0.05</i>), while it was significantly higher in Cefoperazone + Alcohol group than in the other groups at each time point (<i>P</i> &lt; <i>0.05</i>). The third part of results showed that even though the rats died of acute excessive drinking, both blood and hepatic APA and blood acetaldehyde were significantly lower than those in Cefoperazone + Alcohol group (<i>P</i> &lt; <i>0.05</i>).</p> Conclusion <p>APA may provide an auxiliary diagnostic basis for suspected death cases of disulfiram-like reactions, but it needs to be further verified in combination with clinical and forensic practice.</p>