The precision of lattice results depends among other factors on the accurate determination of the excited states contamination. The successful application of chiral perturbation theory to assess these excited states in nucleon observables has lead to the idea to apply it to the B meson sector. In this talk, I will first give an introduction to chiral perturbation for heavy mesons and then present results for the excited states contamination of the B meson decay constant, B -> pi form factors, and neutral B meson oscillation.