The authors describe a case of a well-designed homicidal poisoning in China. A male was treated with starvation, intravenous fluids and antibiotics while in the hospital for acute diarrhea. He suddenly suffered from shortness of breath and subsequently died. A forensic autopsy was carried out, and several specimens were collected for toxicological screening. Propofol was tentatively identified in the blood by GC-MS. Based on the presence of propofol in the blood, a suspect confessed that two other drugs, namely midazolam and vecuronium, were involved in this murder. Analytical drug quantification was then performed by GC-MS and LC-MS/MS. Blood analysis revealed the following: propofol at 0.5 μg/mL, midazolam at 0.098 μg/mL, and vecuronium at 0.10 μg/mL. These results suggest that the cause of death was respiratory depression due to the acute combined effect of several anesthetic drugs administered by the victim's companion.