In this proceedings we study possibility of final state radiation (FSR) in the process of dark matter (DM) decay/annihilation. Two possibilities are considered independently: one-cascade annihilation through intermediate particle (a), and parameterized interaction vertex. The mass of a and vertex parameters are used to try to suppression FSR. Suppression is necessary to avoid limit from cosmic gamma-radiation preventing DM explanation of positron anomaly in CR. Finally, it may seem that a little suppression can be reached by fine-tuning the mass of a, and vertex parameters do not help to do it in the considered cases.