Woman driver is left with horrific gash in her head after a crazed man hurled a metal tool through her car window - leaving her soaked in blood

A manhunt is underway for a thug who hurled a metal tool through a woman's car window and into her head, leaving her soaked in blood.

Tammy Andrews, 45, was driving to the chemist in her white Ford Falcon in Greenfields, south of Perth, at 7pm on Tuesday when a man ran up to her car.

The stranger, who police believe is in his 20s, launched the socket extender through the car window, slicing the right side of her head.

Tammy Andrews, 45, was driving to the chemist when a stranger hurled a piece of metal through her window and sliced her head open

Pictured: The car socket extender the unknown man threw Ms Andrews' car window

'Someone ran from the park and threw the tool through my window and hit me in the side of the head,' she told The West Australian. 

Ms Andrews said her head went numb before she saw the blood.  

She was able to drive a short distance to a friend's place before she was taken to Peel Health Campus. 

'I had 18 staples in my head and today all the bruising in coming out so it is very sore and very traumatic.' 

'I had 18 staples in my head and today all the bruising in coming out so it is very sore and very traumatic,' she said 

The woman said she did not provoke the man 'in any way'. 

'I was just driving. It is very scary and I'm scared to get back in my car because you don't think this will ever happen to you.' 

Police described the man as dark skinned, 170cm tall, stocky build, black hooded jumper and black shorts.

Detectives would like anyone to speak to anyone who witnessed the incident or saw any suspicious activity around the time of the incident. 

Anyone with dash-cam footage or any information is asked to contact Crime Stoppers 1800 333 000 or report online at www.crimestopperswa.com.au