The incident took place at a store on Hawthorn Street in the north of the city shortly after 9pm on Saturday.
Police say they were called to reports of a man spraying a substance at a staff member within the premises.
Emergency services rushed to the scene, and the member of staff, a 24-year-old man, was taken to Glasgow Royal Infirmary for treatment.
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Officers stated that the man responsible fled the area, and enquiries are ongoing to trace him.
A Police Scotland spokesperson said: “Around 9.05pm on Saturday, August 16, we received a report of a man spraying a substance at a staff member at a shop on Hawthorn Street in Glasgow.
“Emergency services attended, and the member of staff, a 24-year-old man, was taken to Glasgow Royal Infirmary for treatment.
“The man responsible made off, and enquiries are ongoing to trace him.”