Colorectal cancer (CRC) is a leading cause of morbidity and mortality. Post-CRC resection complications and lower quality of life (QoL) are associated with a lower long-term survival. Perioperative administration of probiotics/synbiotics might lower prevalence of side effects and improve QoL and survival among CRC patients. Medline, Web of Science, Cochrane database, Embase, and clinical trials registries were searched in January 2020. Altogether, 16 randomized placebo-controlled probiotic/synbiotic clinical trials that included patients undergoing CRC surgery and investigated postoperative complications and QoL side effects were found. Meta-analyses using random-effects model were performed on data from 11 studies to calculate the effects of probiotics/synbiotics on common CRC resection postoperative side effects and complications. Perioperative probiotics/synbiotics administration was associated with lower infection incidence (odds ratio [OR] = 0.34, P < 0.001), lower diarrheal incidence (OR = 0.38, P < 0.001), faster return to normal gut function (mean difference [MD] -0.66 days, P < 0.001), shorter postoperative antibiotics use (MD -0.64 days, P < 0.001), lower incidence of septicemia (OR = 0.31, P < 0.001), and shorter length of hospital stay (MD -0.41 days, P = 0.110). The results support the hypothesis that short-term perioperative administration of probiotics/synbiotics, which are easy to administer, have few side-effects, and are low cost compared with alternatives, might help to alleviate gastrointestinal symptoms and postoperative complications among CRC patients.