Abstract: A system for checking a correct oral hygiene procedure characterised by comprising: a video camera for acquiring the images of the face of a person brushing their teeth with a toothbrush comprising a marker; processing means for analysing said images and for locating the salient points of said face of a person; processing means for analysing said images and for locating said toothbrush; processing means for following the movements of said salient points and for following the movements of said toothbrush; processing means for calculating the movement between said face and said toothbrush and for checking that said relative movement between said face and said toothbrush corresponds with a relative pre-set movement; where said marker is divided into a plurality of areas; and where each of said plurality of areas is coloured, with a colour chosen from a predefined number of colours, to maximise the colour contrast between said areas.