[en] A new approach for calculating higher-order effects in pion multiple scattering is proposed. The theory includes nucleon-nucleon correlations and incorporates the idea of self-consistency. The theory is examined analytically in the case of nonoverlapping scatterers and it is found that: (i) higher-order terms are more moderate in size than found previously; (ii) the Kisslinger anomaly cannot occur; and (iii) the pion mean free path at resonance is comparable to the interparticle spacing at high density. The ideas are developed within the framework of the Foldy-Walecka theory but are applicable in more comprehensive theories. (Auth.)