Background/aim: Endoscopic mucosal resection (EMR) is widely used for treating gastrointestinal polypoid lesions. However, it is currently unclear whether antibiotic administration is necessary after EMR of colon polyps to prevent infection. We aimed to assess whether antibiotic administration is essential in such conditions. Materials and methods: In total, 115 patients with colon polyps were randomly assigned to 3 groups based on the treatment given after EMR: Group A, no antibiotics treatment after EMR (n = 38); Group B, administration of levofloxacin after EMR (n = 38); and Group C, administration of ceftazidime after EMR (n = 39). Results: The colon polyps were completely removed by EMR in all cases without any serious complications. Although infection developed in 2 cases in Group A, it was resolved via levofloxacin injection over 3 days; infection did not develop in any cases in Group B and C. The postoperative infection rate was not significantly different among Groups A, B, and C. After 6 months, we noted that the wound surface had properly healed and there was no relapse of colon polyps in any patients. Conclusion: The use of antibiotics after EMR of colon polyps to prevent infection did not affect the prognosis of patients.