  We review recent investigations on the short distance behaviors of potentials
among baryons, which are formulated through the Nambu-Bethe-Salpeter (NBS) wave
function. After explaining the method to define the potentials, we analyze the
short distance behavior of the NBS wave functions and the corresponding
potentials by combining the operator product expansion and a renormalization
group analysis in the perturbation theory of QCD. These analytic results are
compared with numerical results obtained in lattice QCD simulations.
