An automatic machine for dosing water and dental alginate is disclosed. The machine comprises a pressurized water container and a dental alginate container. In the automatic machine, a predetermined amount of each of those substances is transported from its respective container to a dosing point. During operation of the automatic machine, dental alginate is moved inside the alginate container with the purpose of bringing down residues of alginate adhered to the internal walls of the alginate container. In addition, the automatic machine comprises a control unit with a memory that stores dosing programs, this memory may be programmed in order to handle dental alginate of different manufactures.