The incident happened on the Pershore Road, Stirchley
Police are hunting a man suspected of stabbing a woman close to a gym in Stirchley.
The attack happened near Fitness First on Pershore Road just before 2pm yesterday (July 1).
The woman, who is in her 30s, was repeatedly stabbed.
She was taken to hospital with life-threatening injuries.
The suspected attacker drove away in a silver coloured vehicle.
West Midlands Police believe the man was known to the victim.
Detectives are appealing to anyone who may have witnessed the incident to call them on 101.
If anyone knows of the whereabouts of the man they are advised not to approach him and to call 999.