Nurse Who Killed 3 Patients by Mixing Detergent in Their IV Drips Blames Exhaustion

The 34-year-old admitted to murder but said she didn’t regret it.
nurse, japan, murder, poison, IV drip, elderly, medical, death
The defendant said she was "mentally and physically exhausted" from her job as a nurse. Photo: Getty Images

A former nurse in Japan has blamed what she said was her exhaustion for driving her to kill three elderly patients by mixing detergent into their IV drips in 2016.

Ayumi Kubogi, 34, admitted to the killings in a trial in the port city of Yokohama that started earlier this month. Although she said treating sick patients was “rewarding,” Kubogi told the court on Monday she was “mentally and physically exhausted” from the job and thought about quitting, Japanese broadcaster NHK reported. 


The woman faces a minimum of 5 years to up to life imprisonment or the death penalty for murder. The hospital she worked in, in Yokohama, remains shut nearly five years after the crimes were carried out over three days in September 2016.

At the time, the killings drew public attention to the growing shortage of nurses in the rapidly aging nation, a shortfall that has persisted and was later exacerbated by rising demand for medical care services during the COVID-19 pandemic. 

According to a 2019 study conducted by Japan’s health ministry, the country could face a shortage of up to 270,000 nurses by 2025. Authorities have attributed the supply gap in part to longer life spans and a shrinking workforce owing to low birth rates.

This has worsened the stress experienced by medical professionals in Japan. Nurses and doctors have reported getting burnt out from overwork, a phenomenon widely observed globally during the COVID-19 pandemic.

During the trial, Kubogi said she began developing anxiety three years after she got her nursing certificate in 2008, when she felt at fault for failing to save a patient who died under her care in a different hospital. She was prescribed sleeping pills to cope with her growing anxiety, which followed her throughout her career as a nurse. 


Kubogi said she was also treated badly by patients’ bereaved families, which she said caused her stress, according to NHK. Kubogi moved to the Yokohama hospital in 2015, where a majority of her patients were elderly and terminally ill. 

Two of Kubogi’s victims, aged 78 and 88, died when another nurse inadvertently administered IV drips that Kubogi had mixed with disinfectant. Another victim, aged 88, died directly at the hands of Kubogi after she administered the adulterated fluids.

In a chilling admission, Kubogi told the court she planned to kill four other patients the same month and had mixed detergent into their IV drips. But on Sept. 20, the day Kubogi’s last victim died, one of her coworkers noticed bubbles in a bag and found a hole in the drip’s rubber stopper, indicating someone had tampered with it. The coworker subsequently called the police. Kubogi confessed her crimes to the authorities in June 2018. 

The defendant said she felt no regret about what she had done, “but felt more relieved than anything at that time,” according to the Japanese newspaper Tokyo Shimbun. During court-ordered psychological evaluations, Kubogi was determined to be depressed and mildly autistic, but the doctors said her symptoms were a distant cause of her motive in committing the crimes. 

The trial is expected to conclude on Nov. 9, when a verdict will be given. 

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