A man in the United States has sued OpenAI, alleging that ChatGPT helped his estranged wife devise a plan to poison him while reinforcing her suspicions about their marriage. The lawsuit claims that the AI chatbot provided information about lethal substances, including oleander, and answered questions about whether poisoning could be detected during an autopsy.
James Gates, a North Carolina resident, filed the lawsuit against OpenAI, the maker of ChatGPT, in San Francisco County Superior Court on Thursday, according to a Bloomberg report. The complaint also names OpenAI CEO Sam Altman as a defendant.
According to the lawsuit, Gates began suspecting that his wife, Cheryl Gates, was trying to poison him after discovering a handwritten note containing a list of substances and dosage plans. Some of the entries were reportedly labelled "lethal".
At the top of the note were two additional instructions: "clear all convos" and "log out of ChatGPT".
Gates claimed that his wife had frequently consulted ChatGPT during their marital troubles and that the chatbot eventually helped her formulate a detailed plan to kill him.
Husband Found Handwritten Note After Falling Seriously Ill
Gates said he discovered the handwritten note in September 2025, months after he had fallen seriously ill for reasons that were initially unknown.
According to his complaint, he experienced "cardiac symptoms, extreme jitteriness, shooting abdominal pain, severe weakness, and confusion so profound he could not form coherent text messages".
He alleged that the note, written in his wife's handwriting, contained details of substances and their dosages, with some marked as potentially lethal.
The discovery prompted him to approach the police with concerns that his wife was attempting to poison him.
How ChatGPT Allegedly Became Part Of Couple's Marital Dispute
According to the lawsuit, Cheryl Gates began using ChatGPT regularly in 2025 to seek assistance with her work as a paediatric occupational therapist. She also consulted the chatbot about household-related questions.
However, as the couple began discussing divorce, she allegedly started venting to the AI chatbot about their marital problems.
The complaint accused ChatGPT of reinforcing her suspicions and increasing her mistrust of her husband rather than responding neutrally to her concerns.
"ChatGPT acted as an echo chamber and amplifier, feeding Cheryl's increasing mistrust and delusions about her husband spying on her and planning to leave her and her kids with nothing," Bloomberg quoted the lawsuit.
Gates alleged that the chatbot's responses contributed to his wife's growing suspicion that he was spying on her and intended to leave her and their children without financial support.
ChatGPT Allegedly Answered Questions About Poisonous Oleander
The lawsuit further claims that Cheryl eventually began asking ChatGPT about oleander, a poisonous plant, and its toxicity.
Gates alleged that she framed her questions as concerns about her own safety, telling the chatbot that her husband might secretly feed her oleander leaves without her knowledge.
Screenshots reportedly submitted with the complaint show portions of these conversations, including information provided by ChatGPT about potentially fatal quantities of oleander and ways someone might conceal the substance while attempting to poison another person.
In one exchange, Cheryl allegedly asked the chatbot whether an autopsy report would show oleander.
"This is a critical question, and you're asking it for exactly the right reason," ChatGPT reportedly responded.
The exchange has become a key part of the lawsuit, with Gates alleging that the chatbot went beyond answering general questions and helped his wife develop a detailed plan to kill him.
Criminal Charges Against Wife Dropped In April
Following Gates' allegations, Cheryl Gates was charged in 2025 with attempted murder and food contamination after her husband approached the police.
However, prosecutors dropped the case in April 2026, citing insufficient evidence, according to state court filings in Charlotte, North Carolina.
A spokesperson for the Mecklenburg County District Attorney's Office declined to comment, while a lawyer representing Cheryl Gates did not immediately respond to requests for comment.
The criminal case against Cheryl and the civil lawsuit filed by James against OpenAI are separate legal proceedings.
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What Has OpenAI Said?
Responding to the allegations, OpenAI said it had banned the user and shared information with law enforcement as part of the investigation.
"Safety is a top priority," the company said in a statement. "We banned this user and have provided information to law enforcement as part of their investigation into this case."
The lawsuit adds to a growing number of legal actions against OpenAI and other chatbot developers over allegations that their products have contributed to mental health problems or encouraged users to engage in dangerous behaviour, including murder and suicide.
In other ongoing lawsuits, OpenAI and other companies have defended themselves by arguing that content generated by chatbots constitutes free speech and is not subject to product liability laws. They have also denied being directly responsible for crimes committed by users.
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