  QCD at long distances can be described by the chiral Lagrangian. On the other
hand there is overwhelming evidence that QCD and all non-abelian theories admit
an effective string description. Here we review a derivation of the (intrinsic)
parity-even chiral Lagrangian by requiring that the propagation of the QCD
string takes place on a background where chiral symmetry is spontaneously
broken. Requiring conformal invariance leads to the equation of motion of the
chiral Lagrangian. We then proceed to coupling the string degrees of freedom to
external gauge fields and we recover in this way the covariant equations of
motion of the gauge-invariant chiral Lagrangian at p^2 order. We consider next
the parity-odd part (Wess-Zumino-Witten) action and argue that this require the
introduction of the spin degrees of freedom (absent in the usual effective
action treatment). We manage to reproduce the Wess-Zumino-Witten term in 2D in
an unambiguous way. In 4D the situation is considerably more involved. We
outline the modification of boundary interaction that is necessary to induce
the parity-odd part of the chiral Lagrangian.
