Police were called to Royal Exchange Square at 3.25am on Monday, September 12, after a fight broke out at the corner of Queen Street.
The men, aged 38, 42 and 46 were taken to Glasgow Royal Infirmary for treatment along with a 48-year-old woman.
All four have since been released from hospital.
On Monday morning, part of Royal Exchange Square was closed off as officers worked at the scene.
A Police Scotland spokesman said: “Police received reports of a disturbance involving several people in Royal Exchange Square at the corner of Queen Street.
“Three men aged 38, 42 and 46 and a woman aged 48 were taken to Glasgow Royal Infirmary and have since been released following treatment.”
It is believed police are following a positive line of enquiry.