AbstractIn a differential absorption experiment the induced infrared transitions from the excitonic 1s to the 2p levels in Cu2O have been investigated. Intermediate densities of 1s excitons were created by cw‐laser excitation while the interexcitonic 1s to 2p transitions were probed simultaneously, using Fourier spectroscopy. Our data give evidence for a surprisingly large splitting of the 2p level (≈3.7 meV) the origin of which is a matter of speculation. An analysis of lineshape and width of the transitions results in a ratio of the effective masses m1s/m2p which deviates from the literature value.