Background: Acute colonic bleeding is a serious medical emergency. Computed tomography mesenteric angiography (CTMA) has become a critical diagnostic tool, enabling rapid identification of active haemorrhage. In many tertiary centres, interventional radiology guided angiography with embolisation has emerged as an effective and minimally invasive first line method for achieving haemostasis. While effective, the procedure carries a risk of colonic ischaemia. This study evaluates the impact of timing from CTMA to angiography on embolisation success, and identifies clinical and biochemical predictors of post-embolisation colonic ischaemia. Methods: A retrospective cohort study was conducted at Liverpool Hospital (2015–2017) involving 58 patients with acute colonic bleeding and positive CTMA. Patient demographics, medication history, procedural details, and post-procedure outcomes were analysed. Inflammatory markers (CRP, WCC) were monitored over three days post-embolisation. Statistical analyses included univariate and multivariate testing with significance at p < 0.05. Results: Of 58 patients, 38 underwent embolisation. Successful embolisations occurred significantly earlier post-CTMA (mean 80 minutes sooner) than unsuccessful cases. Colonic ischaemia occurred in 10% of patients post-embolisation, with most cases involving superior mesenteric artery branches. Anticoagulant use was significantly associated with ischaemia (p = 0.05). Patients who developed ischaemia had a steeper rise in CRP compared to non-ischaemic cases (D2 CRP: 139 vs 53 mg/L). Three patients required surgical resection due to ischaemic complications. Conclusion: Prompt angiography following CTMA improves embolisation success. Anticoagulation and rising CRP are potential predictors of post-embolisation ischaemia. These findings support early intervention, selective embolisation strategies, and vigilant post-procedure monitoring, particularly in anticoagulated patients.