Ischaemic stroke is extremely common in western societies contributing to 70-85% of strokes, one of the leading causes of mortality and long-term disability. Despite advancement in preventive measures, the total number of strokes is set to rise in the future due to increasing numbers of aging populations across the world. Diabetes as a risk factor for stroke has been well established. There are also emerging evidence to suggest glucose level management in acute stroke phase as a therapeutic target may be beneficial, albeit remains controversial. One of the issues in difficulty in interpreting study findings is their heterogeneity. In this article, we provide epidemiological, basic science, clinical observational and trial evidence leading to the current practice of regarding blood glucose as the therapeutic target in acute ischaemic stroke setting.