The results of experimental studies of the fluorescence response of polylactide foams saturated with rhodamine 6G and composites used for their preparation in the region of transition from spontaneous fluorescence to stochastic laser generation are presented. A small increase in the threshold of stochastic laser generation in foamed composites compared to the expected one is interpreted as a result of the contribution of the waveguide mode of fluorescence propagation in the polymer matrix.. Keywords: polylactide foam, spontaneous fluorescence, stochastic laser generation, waveguide mode.