A Houston oncologist is facing charges for allegedly lacing her lover’s coffee with a sweet-tasting chemical, poisoning him to the point of causing renal failure.

Ana Maria Gonzalez-Angulo, a breast cancer oncologist at the University of Texas M.D. Anderson Cancer Center, was charged last week with aggravated assault against Dr. George Blumenschein, a specialist in lung and head and neck cancers at the institution. The two were in "a casual sexual relationship," according to a criminal complaint.

The complaint said Blumenschein, who joined the cancer center in 2000, suffered a protracted loss of the use of his kidneys and is still being treated for it. M.D. Anderson officials would not say whether he is back at work.

Gonzalez-Angulo's lawyer, Derek Hollingsworth, told the Houston Chronicle that she is "completely innocent."

"She is a distinguished citizen and scientist, and these allegations are totally inconsistent with her personal and professional life," Hollingsworth said in a statement.

Gonzalez-Angulo, who joined M.D. Anderson in 2003, was booked May 30 and is now free on $50,000 bail.

M.D. Anderson officials said Gonzalez-Angulo is on paid administrative leave, but they declined to comment further.

Authorities allege that Blumenschein was poisoned on Jan. 27 when he was at Gonzalez-Angulo's Southside Place townhome.

The report said that after Blumenschein complained to his lover about a sweet taste in his drink after asking for black coffee, she replied that she had added Splenda. She made him another cup, and Blumenschein said that despite its similarly sweet taste, he drank it, too.

Within four hours, he began experiencing slurred speech, poor balance and a loss of fine motor skills. He was taken to an emergency center 16 hours later, where he was found to have central nervous system depression, cardiopulmonary complications and renal failure. He later had to undergo dialysis.

A 24-hour urine test found crystals consistent with ethylene glycol poisoning, according to the complaint. It also said a county toxicologist concurred with the assessment.

A toxicology report by a third expert indicated Blumenschein's acute severe metabolic acidosis "more likely than not" was due to ethylene glycol poisoning. According to a criminal complaint filed with the Harris County District Attorney’s Office on May 29, the chemical was described as a “deadly weapon.”

Ethylene glycol, a solvent and starting material for the synthesis of more complex molecules, is an odorless and colorless, yet sweet-tasting, toxic chemical that can be found in antifreeze. According to a cancer center research administrator, it is present in all M.D. Anderson laboratories. As a result, Gonzalez-Angulo had access to the substance, according to investigators.

M.D. Anderson said that Gonzalez-Angulo was suspended with pay. According to court documents, she was also directed to stay at least 200 feet away from Blumenschein’s residence and workplace, as well as to surrender her passport.

Although Blumenschein survived the poisonous attack, the criminal complaint said that he is still suffering from kidney damage. M.D. Anderson has neither confirmed nor denied that Dr. Blumenschein has returned to work.

The Associated Press contributed to this report.

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