  We use chiral perturbation theory to investigate hadronic properties in
strong electric and magnetic fields. A strong-field power counting is employed,
and results for pions and nucleons are obtained using Schwinger's proper-time
method. In the limit of weak fields, we accordingly recover the well known
one-loop chiral perturbation theory results for the electric and magnetic
polarizabilities of pions and nucleons. In strong constant fields, we extend
the Gell-Mann-Oakes-Renner relation. For the case of electric fields, we find
that non-perturbative effects result in hadron decay. For sufficiently strong
magnetic fields, the chiral analysis confirms that the nucleon hierarchy
becomes inverted giving rise to proton beta-decay. Properties of asymptotic
expansions are explored by considering weak field limits. In the regime where
the perturbative expansion breaks down, the first-order term gives the best
agreement with the non perturbative result.
