The anti-Epidermal Growth Factor Receptor monoclonal antibodies (anti-EGFR MoAbs) are beneficial in the treatment of wild type (WT) KRAS colorectal cancer, but are burdened by serious toxicities. We conducted a systematic review and meta-analysis to determine incidence and relative risk (RR) of severe and life-threatening diarrhoea and mucositis in colorectal cancer patients and WT-KRAS subpopulation. PubMed and Embase were searched for trials comparing the same therapeutic regimens with or without anti-EGFR for colorectal cancer. Data on severe and life-threatening diarrhoea and mucositis were extracted from 18 studies involving 13,382 patients. Statistical analyses calculated incidence of AEs, RRs and 95% confidence intervals by using either random or fixed effects models. Patients receiving anti-EGFR MoAbs showed an increased risk of diarrhoea (RR: 1.66, CI 1.52-1.80) and mucositis (RR: 3.44, CI 2.66-4.44). The risk was similar among WT-KRAS patients. Prevention and risk reduction strategies of these AEs are mandatory to optimize clinical outcomes