This contribution summarizes the state of the art concerning the simulation with computational fluid dynamics of reacting flows with a particular focus on the interaction between turbulent mixing and chemistry. When dealing with nonisothermal gas-phase reactions (e.g., combustion) and rapid reactions (e.g., acid–base) in the liquid phase, the calculation of the chemical source term becomes challenging. The different computational methods proposed in the last 3 decades to deal with this problem are discussed and their application in the context of direct numerical simulation, Reynolds-averaged Navier–Stokes equation, and large-eddy simulation approaches are illustrated.