The attack was reported at about 8:30 p.m. Tuesday in the 400 block of 28th Avenue.
The 56-year-old victim got into an argument with a 31-year-old man, who threw the stool, striking her in the face, according to police.
The suspect then drove the victim to St. Mary's Medical Center where hospital staff reported the incident to police.
Police spokesman Officer Carlos Manfredi said he did not know the relationship between the suspect and victim.
The suspect, whose name was not immediately available this morning, was arrested on suspicion of aggravated assault, police said.
The victim was treated at the hospital for her injuries, which included a cut above her eye.