Jack Chen prepped and sipped the same cup of hot lemonade most mornings, but it wasn’t until suffering stomach ulcers and a swollen esophagus that he noticed a “chemical taste.” That’s when he decided to install hidden cameras inside his Irvine home.

Chen, a radiologist, lived in a comfortable house with his wife, dermatologist Yue “Emily” Yu, and their 7- and 8-year-old children.

But Chen was growing concerned about their 10-year marriage. In court documents filed in a request for a restraining order, he described an abusive and at times violent relationship; Yu hit and cursed at the children and, as the marriage turned sour, yelled at them when they spent time with their father, Chen alleged.

Then, on July 11, he said, he looked at the hidden-camera video to confirm a nagging suspicion.

“I found out my wife,” the 53-year-old wrote in a court declaration, “has poisoned me with Drano to try to kill me.”

On Aug. 4, Irvine police searched the couple’s home and arrested Yu, 45, after Chen turned over the video, authorities said. The next day, Chen filed for divorce and asked the court for a temporary restraining order, including multiple stills from videos that he said show his wife calmly spiking his morning drink on three separate occasions.

Yu, who has since been released from county jail on $30,000 bail, denied the allegations and, through an attorney, called her husband’s statements defamatory.

Yu “vehemently and unequivocally denies ever attempting to poison her husband or anyone else,” her attorney, David E. Wohl, said in a statement. She “has never engaged in harmful conduct toward anyone, including members of her family.”

No criminal charges have been filed in the case, but a judge has since granted a temporary restraining order against Yu. A hearing is set for Thursday in family court.

In divorce filings, Chen has asked for Yu to move out of their home and for him to retain full custody of their children, who he said “have suffered physical, verbal and emotional abuse by their mother.”

Yu would often insult the children, Chen alleged, calling them “stupid,” “dumb” or at times using a Chinese phrase that translates to “go die.” To discipline the children, Chen claimed in court, Yu sometimes deprived them of sleep, waking them up when they fell asleep without her permission.

Yu’s attorney accused Chen of making false allegations in order to gain an upper hand in the divorce proceedings.

“We are very concerned that these defamatory, false allegations have been made by Mr. Chen in an attempt to gain an advantage in the divorce and custody case he filed against Ms. Yu, a day after she was arrested,” Wohl wrote. “On top of that it is hard to imagine anyone believing that Dr. Chen could start drinking Drano nearly 6 months ago and not figure out he was ingesting a caustic chemical until last week.”

Chen’s attorney, Steven Hittelman, said his client started to experience suspicious symptoms in March and has since been diagnosed with two stomach ulcers, gastritis and a swollen esophagus.

According to Chen’s claims in the family court case, his hidden-camera videos show Yu pouring liquid from a bright orange container into Chen’s cup on July 11, 18 and 25.

On July 18, Hittelman said, video shows Chen preparing his tea, taking a sip, and then placing a sheet of plastic wrap atop it before leaving the room.

Yu is then seen grabbing the orange bottle from under the sink, lifting the plastic, pouring a bit of the bottle’s contents and putting the wrap back over the cup, according to Chen’s attorney.

“She sits back like nothing had happened,” Hittelman said.

A similar sequence occurred July 25, Hittelman said, but after reviewing the first video, Chen had stopped drinking the tea.

When Chen reached out to Hittelman and showed him the video, the family law attorney said he “told him he was in the wrong office and told him he needed to go to the Irvine Police Department.”

Wohl, a criminal defense attorney based in Riverside, said neither he nor Yu had viewed the videos but still challenged the description of them in Chen’s court declaration, saying that Yu has been a well-respected physician for years and that the videos would not show her doing anything illegal.

“Her goal [has] always been to help people and never to harm them,” Wohl said.

According to the California Medical Board, Yu has been a licensed physician since 2010 and has been affiliated with Providence Mission Hospital.

The hospital said in a statement that it was aware of the arrest and cooperating with police, but called the incident a “domestic matter.”

“We want to reassure our community that there has been no impact to our patients,” the statement said.

On Sunday, Yu’s online biography appeared to have been removed from the hospital’s website.

In response to questions from The Times, Wohl also alleged that Chen did not submit the complete videos to family court because they would show Yu did not do “anything illegal or abusive at all.”

“He submitted the stills because he took parts of the video that he thought would support his false allegations,” Wohl said. “Mr. Chen’s claims that my client has tried to poison him for months are flat out not true.”

Hittelman said that the videos were handed over to a detective and that he submitted only stills to the court at the request of the Irvine Police Department and the Orange County district attorney’s office, which are both still investigating the case. Submitting the videos in family court, he said, would make them public and possibly hinder the investigation.

Chen currently has custody of the two children and, Hittelman said, has not had contact with his wife since the day she was arrested. Yu called Chen from jail, Hittelman said, and asked him to bail her out.

He refused to do it, the attorney said.