The present invention regards an applicator device for the preparation and application of at least one medical substance, preferably a coloured liquid, comprising: a hollow chamber having a hosting end and an opposite distal end in communication with means for contact with the patient; a cartridge slidingly inserted into said hollow chamber, containing at least one first medical substance, and having a first end external to the hollow chamber, and a second end completely inserted into the hollow chamber; a breaking means positioned at the distal end, capable of establishing a fluid communication between the internal of the cartridge and the means for contact with the patient; said second end being sealed by a filled double layer closure system containing at least one second substance, preferably coloured, mixable and/or soluble with the first medical substance contained in the cartridge.