Hadron therapy uses light charged particles beams (mainly proton and 12C ions) to irradiate tumors. These beams present a ballistic advantage with a maximum energy deposition at the end of the path. A large dose can be delivered inside a deep tumor while the surrounding healthy tissues are preserved. There is an obvious advantage in using these beams but the beam control has to be achieved and all the physical processes leading to the energy deposition have to be fully under control. This treatment protocol requires accurate control devices and a good knowledge of the physical processes occurring all along the path of the projectile in human tissues. In this report, we will present one example of a beam monitor for the proton therapy. We will also present the experimental program which has been initiated to obtain fundamental data on the nuclear fragmentation process.