  We compare the properties of three-body systems obtained with two-body
potentials with Pauli forbidden states and with the corresponding phase
equivalent two-body potentials. In the first case the forbidden states are
explicitly excluded in the calculation. Differences arise due to the off-shell
properties of these on-shell equivalent potentials. We use the adiabatic
hyperspherical method to formulate a practical prescription to exclude Pauli
forbidden states in three-body calculations. Schematic as well as realistic
potentials are used. Almost indistinguishable results are obtained.
