Police were called at 1.50am on Tuesday (18 February) to Junction Road in Burgess Hill to a report of a fight involving a group of teenagers.
When officers arrived they arrested three boys aged 17, 15 and 15 and an 18-year-old man, all from Burgess Hill, on suspicion of assault.
All four were questioned before being released on bail until April 12 while officers carry out further inquiries.
An 18-year-old man from Burgess Hill was treated by paramedics for cuts to his hands and swelling around his eye.
A number of weapons were seized including a small knife and a metal pole.
Anyone with information can call 101 quoting serial 71 of 18/2, email firstname.lastname@example.org or call the independent charity Crimestoppers anonymously on 0800 555111.