The attack happened Friday night in the emergency room, when Mary Perez was admitted for breathing problems. She suffered cuts and bruises when 29-year-old Zebest reportedly hit her with an IV pole.
At the time, Zebest was being taken to the ER for a medical evaluation.
Perez told her daughter he went berserk when doctors told him he had to be placed in psychiatric care.
"My mom says the man opened the curtain, closed it, picked up the IV pole and used the base of the pole to hit her in the head," Perez's daughter Tirsa Ledesma said through a translator. "She put up her arms to defend herself but he kept hitting her."
The hospital says sheriff's deputies stationed in the emergency room were able to subdue Zebest. Her daughter says the damage was already done.
"They found her bloody, she was bleeding from her head," Ledesma said. "Her body was bruised and her arms were bleeding.
Last fall, 57-year-old Lynne Spalding was found dead in a hospital stairwell, 17 days after she was reported missing from her room. Investigators later found both the hospital and the sheriff's department at fault.
The attorney for the Spalding family told ABC7 News, the promises by Sheriff Ross Mirkarimi to increase security aren't working.
"This woman could have been beaten or choked to death," Haig Harris said. "There is no security or safety at San Francisco General Hospital."
The hospital says Perez is in good condition, but she'll stay over one more night for observation.