Reactions is a small handy freeware for generation of all possible reactions between specified substances (pure minerals and components of solid solutions, oxides and chemical elements) with selection of the arbitrary set of linearly independent reactions. This program may be useful for education, for analysis of diagrams (petrogenetic grids and results of multi-equilibrium geothermobarometry), for balancing of reactions involving minerals with real compositions, for evaluation of solid solution end-members, etc.