Meson production in nucleon-nucleon collisions

I review some recent works on meson production in nucleon-nucleon collisions. In particular, I report on an investigation of the reaction NN -> NN pi near threshold where the production amplitude has been evaluated within chiral perturbation theory up to next-to-leading order, using a counting scheme that takes into account the large scale introduced by the initial momentum. With regard to other meson-production reactions I focus on a phenomenological analysis of the I >/I (0) pound production ratio in pp collisions