Fatal Levels of Sedative Found in Zhou’s Autopsy

Toxicology studies for Mengyao “May” Zhou ’04 found toxic levels of diphenhydramine, a sedative and antihistamine, in her system. Zhou, a Stanford University graduate student, was found dead in the trunk of her car on Jan. 25 of an apparent suicide.

Zhou’s toxicology tests detected diphenhydramine at 6.15 mg/L, exceeding the “toxic range” of 1–5 mg/L, according to a Sonoma County Coroner’s Office press release. Diphenhydramine is an ingredient in over-the-counter drugs such as Benadryl and sleep aids.

“No other common acidic, neutral or basic drugs [were] detected,” the press release stated. “No blood or urine ethyl alcohol [was] detected.”

Despite the completion of an autopsy, the Santa Rosa police have not yet ruled on the cause of death or commented on the role of diphenhydramine in Zhou’s death.

Yitong Zhou, May Zhou’s father, is convinced his daughter did not commit suicide.

“Nobody believes she killed herself … just the police,” he said to The Mercury News. Yitong Zhou also told the paper he was considering hiring his own forensics expert and exhuming his daughter’s body.

Zhou’s father has also questioned the source of the diphenhydramine, saying there are no receipts showing its purchase. “The tests don’t mean anything if you can’t find out where [the drugs] came from,” he told The Palo Alto Daily News.

Yitong Zhou is also suspicious of the transfer of “a large sum of money” on the night his daughter died, he told The Palo Alto Daily News. “This means she didn’t think she would die. Otherwise, why would she move the money?”

The investigation into Zhou’s death still remains open.