Police said the woman stole a Houston Fire Department ambulance just after 10pm and took it for a ride, seconds after paramedics dropped off a patient at St. Joseph's Hospital.
According to investigators, EMS workers transported a patient to St. Joseph's, but when they returned to the ambulance, it was gone.
Another ambulance found the stolen emergency vehicle nearly 45 minutes later on Pierce near Hutchins.
Police believe the woman was under the influence of drugs when she allegedly stole the ambulance. Officials said the vehicle wasn't damaged.
The woman was taken into custody and faces charges of unauthorized use of a motor vehicle.