Combining mechanical bowel preparation with oral antibiotics significantly reduces complications after elective colectomy for colon cancer.

• Surgical site infection dropped from 8.7% without prep to 5.0% with combined prep.
• All bowel prep regimens lowered the risk of postoperative complications versus no prep, with combined prep showing the best relative risk reduction (infection: 0.60, leak: 0.66, any complication: 0.70).

The effectiveness of oral antibiotics in bowel prep holds across varying body mass indexes.

• Mechanical prep alone was not superior for right-sided resections.