HOUSTON — A Texas oncologist had a “fatal attraction” to a fellow physician who also was her lover, and poisoned him by lacing his coffee with ethylene glycol after he rejected her, prosecutors said Monday.

“The evidence is going to show she became absolutely and totally obsessed,” Justin Keiter, an assistant Harris County district attorney, said during opening arguments in the aggravated assault trial of Ana Maria Gonzalez-Angulo, 43, a breast cancer doctor based at Houston’s famed Texas Medical Center.

But Andy Drumheller, one of Gonzalez-Angulo’s lawyers, told jurors in his opening statement that the relationship between his client and lung cancer physician and researcher George Blumenschein was consensual, that it was not over at the time he was poisoned and that other people may be responsible. ” ‘Fatal attraction’ is complete hyperbole and exaggeration,” Drumheller said.

Blumenschein and Gonzalez-Angulo met at the medical center, and their work evolved into a “casual sexual relationship,” according to a criminal complaint. Prosecutors said Blumenschein eventually ended his affair with Colombian-born Gonzalez-Angulo, spurning her in favor of his 10-year live-in girlfriend, with whom he was trying to have children.

Blumenschein then survived kidney failure after Gonzalez-Angulo made and served him two cups of tainted coffee last year, prosecutors said. Ethylene glycol is common additive in automotive antifreeze but also is used in cancer center labs, where the two worked.