Background & aims Cinnamon seems to be highly bioactive, appearing to mimic the effect of insulin through increased glucose uptake in adipocytes and skeletal muscles. This systematic review and Meta analysis examined the effect of cinnamon on glycaemic control in patients with Type 2 Diabetes mellitus. Methods A systematic literature search was conducted from the earliest possible date through to 01 August 2011. Search terms included free text terms, MeSH and Medline medical index terms such as: “cinnamon”, “cinnamomum”, “cinnamomum cassia”, “cinnamomum zeylanicum”, “type 2 diabetes mellitus”. Each was crossed with the term “diabetes mellitus”. In addition, references of key articles were hand searched. Results A total of 6 clinical trials met the strict inclusion criteria and considered a total of 435 patients; follow up between 40 days–4 months, doses ranging from 1 g to 6 g per day. Meta-analysis of RCTs showed a significant decrease in mean HbA1c [0.09%; 95% CI was 0.04–0.14] and mean FPG [0.84 mmol/l; 95% CI was 0.66–1.02]. Conclusions Use of cinnamon showed a beneficial effect on glycaemic control (both HbA1c and FPG) and the short term (<4 months) effects of the use of cinnamon on glycaemic control looks promising.