A humidification system of a dispensing head of a dosing machine of fluid products, where the dispensing head includes a closing device having a cup, which can be moved between a distal inoperative position and an operative position where the dispensing head is isolated from the environment. The humidification system automatically generates a humid environment inside the cup, in the proximal position of the closing element, by means of a Peltier cell inserted in a forced flow duct of ambient air. The condensed and/or frosted water from the Peltier cell is fed from a collecting tank to the cup of the closing element automatically through a control unit.