Pupils at Dukeries Academy were warned to keep away from an area near the school yesterday after a fight be out between three men.
Police say they were called to an area behind the Dukeries information and agency centre on Whinney Lane at 12.15pm on Tuesday.
Three men in their 20s and 30s were found to have been arguing and threatening each other.
No-one was arrested but one man had to be taken to hospital after being hit with a bat.
Police had advised the school to keep students indoors as a precaution during the incident.