Summary It is shown that the ϱ-mesonic final-state interaction could give rise to the observed asymmetries in the η0 → 3π decay. A dynamical model is presented which explains both the branching ratioP(η0→3π0)/P(η0→π+)+π-+π0) and the existence of a large asymmetric component in the (η0→π+)+π-+π0) decay. The model predicts a relatively small symmetric constant amplitude. It is shown that, in this model, the symmetric
constant amplitude vanishes in the limit of the exact 8U3 symmetry and of a constant η-π coupling. A similar discussion is given for the K → 3π decay. Possible effects of the σ0 dipion are also discussed.