The paraquat murders were a series of indiscriminate beverage poisonings carried out in western and central Japan in 1985. The drinks were placed in and around vending machines, where the victim would consume the beverage. All the beverages were poisoned with the herbicide paraquat dichloride, except for one which was poisoned with diquat. The most targeted beverages were the energy drinks Oronamin C and Real Gold. The first known case was on April 30, in Fukuyama. At least 12 died and 35 became seriously ill, in what is possibly the deadliest product-tampering case in history. Warning labels and leaflets were posted around Tokyo, and on many of the 5.2 million vending machines across Japan. Police were unable to gather any evidence about the murders, and the case remains unsolved.

The first victim was poisoned on April 30, 1985. The victim drank a bottle of Oronamin C, a vitamin energy drink,^[1] that was left on top of a vending machine in Fukuyama, Hiroshima Prefecture. He fell ill and died on May 30.^[2][3][4] The bottle was laced with paraquat dichloride, a herbicide used to control weeds. Paraquat is a highly toxic chemical to humans that can destroy the body in hours to days. At the time, it was widely available in Japan, because it could be bought without a prescription or identification. Those who bought it had to prove they needed it for agricultural purposes. It was used by 1,402 people to commit suicide in Japan in 1984.^[3][5][6]

At the time, Ohtsuka Pharmaceutical, who made Oronamin C, had a buy one, get one free promotion of the drink to combat low sales among young people. It was especially popular among middle-aged men in Japan. Taking advantage of the promotion, the criminal laced Ornamin C bottles with paraquat and placed them in and around vending machines, to make customers think they got the promotion.^[1][2][3][7] The poisonings primarily occurred in western and central Japan, and Tokyo. Oronamin C and the energy drink Real Gold were the primary drinks targeted, though some also died from drinking Coca-Cola.^[5][7] One of the poisonings used diquat instead of paraquat.^[7]

On September 5, 44-year old executive Takashi Sakai drank two vitamin drinks, which he died from 6 weeks later.^[3][5] On September 11, 52-year old Haruo Otsu drank from a free bottle of Oranamin C in Tokyo. He died 52 hours later.^[2][3] On September 25, a man in the western prefecture of Wakayama was hospitalized after falling ill, and on September 26, a 40-year old woman in the western prefecture of Shizuoka fell ill.^[8] Either Takashi Sakai or a 17-year-old girl from Saitama were the last victim of the murders.^[3][5]

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