  A review of the modern theory of hadronic atoms based on the non-relativistic
effective Lagrangian approach and ChPT, is given. As an application of the
general framework, we consider the decay of the pi+pi- atom into two neutral
pions, and the energy-level shift of the pi-p atom. The analysis of the decay
width of the pi+pi- atom has been carried out at the first non-leading order in
isospin breaking, and at O(e^2p^2) in ChPT, that results in an accurate
theoretical prediction for this quantity. The study of the pi-p atom
energy-level shift within the same approach clearly demonstrates the necessity
to critically reaccess the values of the pi N scattering lengths, extracted
from the energy-level shift measurement by means of the potential model-based
theoretical analysis. The construction of short-range hadronic potentials from
field theory is also discussed.
