In the standard cosmological paradigm dark matter is modelled as a non-collisional fluid made of non-relativistic stable and neutral massive particles, this assumptions about the features of dark matter are required to predict diverse astronomical and cosmological observations such as the spectra of background cosmic radiation and its anisotropies and the matter distribution at scales above O(100 Mpc) . Nevertheless, the possibility that dark matter is made of non stable particles is observationally viable, as long as dark matter half-life is much larger than the age of the universe. In this talk I will brieflty present some constraints to the half-life and the fraction of decaying dark matter according to observations of redshift space distortions in the large scale structure distribution.