The xenon-sensitized photolysis of hydrogen sulphide and ethane has been performed. The rate constant of the excitation transfer from the Xe(3P1) resonance state to hydrogen sulphide and ethane has been measured to be 3 × 10−10and 4 × 10−10cm3-molec−1S−1. On the basis of the dependence of the hydrogen quantum yield on the xenon pressure at different hydrogen sulphide and ethane pressures the three-body decay of the Xe(3P1) state with xenon atoms and hydrogen sulphide or ethane taking a part in the process has been experimentally shown to have a rate constant of approximately 1 × 10−28cm6molec−2S−1. Using Collins-Lee theory confirms the reliability of this high value.