The man targeted the 19-year-old as she went to get food from McDonald's on Maryhill Road in Glasgow, after a night out at nearby Frampton's club.
Police said five women aged between 19 and 51 suffered irritation to their eyes and skin and were taken to the Western Infirmary after being sprayed with gas from the canister at 2.10am yesterday.
The suspect is described as white, aged between 25 to 35 and had shaven brown hair. He had a scar on the left side of his face running from ear to cheek and wore jeans, a grey cardigan or zip top, a black bodywarmer and black leather gloves.
Detective Sergeant Lesley-Ann McGee described the attack as "a very frightening thing to happen". Anyone with information is asked to call police on 101.