We report transient absorption, saturation measurements on lead sulfide colloidal nanocrystals at the first and second exciton energies and fit the results to a model incorporating intraband and interband relaxation processes. We study in detail the Auger recombination from the first excited state, which takes place when more than one electron-hole pair is excited in a dot. We find an Auger coefficient of 4.5 x 10(-30) cm(6)/s for dots of 5.5 nm diameter' and observe saturation of the absorption bleaching when the (8-fold degenerate) first level is filled. We develop a model for the absorption dynamics using Poisson statistics and find a good fit with our experimental measurements.