Remarks on e+e- annihilation into hadrons in quantum field theory

We show that the absorptive effect of particle production on e⁺e^- annihilation reactions is to reduce the cross sections and give a constant value to R=σ(e⁺e^--->hadrons)σ(e⁺e^--->μ⁺μ^-). In the approximation of summing leading terms, this effect simply gives a factor s^-a to all cross sections.