By Lisa Maria Garza

DALLAS (Reuters) - A Texas hospital placed an oncologist on leave after she was charged with spiking her lover's coffee with a sweet-tasting chemical poison, a hospital spokeswoman said on Tuesday.

Ana Maria Gonzalez-Angulo, a breast cancer doctor at the University of Texas M.D. Anderson Cancer Center in Houston, was charged May 29 with aggravated assault of Dr. George Blumenschein, another cancer specialist at the institution.

The two were in "a casual sexual relationship," according to a criminal complaint.

The complaint said Blumenschein told prosecutors that Gonzalez-Angulo served him coffee that had an "odd taste" but he drank it after she told him it included the artificial sweetener Splenda. Blumenschein added that he always prefers black coffee, the complaint said.

Hours after drinking a second cup with a similar taste, Blumenschein experienced slurred speech, loss of motor functions and balance. He was rushed to a hospital and diagnosed with central nervous depression, cardiopulmonary complications and renal failure, which later required dialysis.

A urine test found crystals consistent with ethylene glycol poisoning, according to the complaint. Ethylene glycol, a chemical used in antifreeze and medical research, is present in all M.D. Anderson laboratories, an administrator said in the complaint.

Hospital spokesman Laura Sussman declined to give the date when Gonzalez-Angulo had been placed on leave.

Gonzalez-Angulo has been released on $50,000 bail and is scheduled to appear in court next month.

(Reporting By Lisa Maria Garza; Editing by Greg McCune)