A graphical user interface for displaying blood glucose information is disclosed. The graphical user interface comprises a trend window arranged to display blood glucose levels of a user on a timeline and a magnifying window superimposed on a segment of the timeline, the relative position of the magnifying window with respect to the timeline being movable. The graphical user interface also comprises a magnified window arranged to display, over an area which is larger than the magnifying window, the information contained in the segment of the timeline and at least one contextual information window arranged to display, over an area of the same size as the magnified window, information which is contextual to the blood glucose levels.
