Clinical cases involving antibiotic poisoning and death are mainly due to antibiotic overdose or patients with a particularly sensitive constitution.In the paper,taking an illegal practice of medicine for example,liquid chromatography-tandem mass spectrometry(LC-MS/MS)was carried out to detect lincomycin,ceftriaxone,and dexamethasone in suspected allergic deaths caused by antibiotics.Besides,combined with scene investigation,autopsy,pathological examination,and toxicology test,it was confirmed that the death was caused by an allergic reaction to antibioticsin.On the one hand,the research results can fill in the blank of simultaneous determination of lincomycin,ceftriaxone and dexamethasone in human plasmas by LC-MS/MS and fill in the data of death due to antibiotic allergy,and on the other hand,the research results can provide methods and data references for the clinical and forensic identification of antibiotics allergy and death cases.Furthermore,this article has summarized the forensic indications and tests of antibiotic allergy deaths,which can provide reference for the investigation of such cases and forensic toxicology.