The paper examines the effect of rationing outputs and inputs on producer behaviour. Full representation of the modified supply-demand system after rationing, including shadow prices for the constrained netputs, is derived from the unrestricted profit function before rationing, and vice-versa. Attention is focused on cross-price effects which have been less explored than own-price effects which obey to the Le Chatelier principle. The theoretical framework is applied to the EC agricultural sector in order to analyse...