  We explore the breaking of Lorentz and CPT invariance in strong interactions
at low energy in the framework of chiral perturbation theory. Starting from the
set of Lorentz-violating operators of mass-dimension five with quark and gluon
fields, we construct the effective chiral Lagrangian with hadronic and
electromagnetic interactions induced by these operators. We develop the
power-counting scheme and discuss loop diagrams and the one-pion-exchange
nucleon-nucleon potential. The effective chiral Lagrangian is the basis for
calculations of low-energy observables with hadronic degrees of freedom. As
examples, we consider clock-comparison experiments with nuclei and
spin-precession experiments with nucleons in storage rings. We derive strict
limits on the dimension-five tensors that quantify Lorentz and CPT violation.
