Mechanochemistry, a branch of solid-state chemistry, analyzes processes which can occur in solids due to the application of mechanical energy. This energy is supplied by high-energy milling. The mechanochemical approach belongs to the group of procedures that intensify the course of processes by producing various surface and bulk defects in treated solids. The accumulated energy acquired by milling is utilized in subsequent processes. In principle, the potential of mechanochemistry can be applied in cases, where the economic demand, the high temperatures as well as wet processes are under consideration. Several applications of mechanochemistry will be illustrated to demonstrate its potential in such apparently distinct fields like extractive metallurgy, materials engineering, and medicine.