  The propagation and decay of neutral B-mesons can be described in terms of
quantum dynamical semigroups; they provide generalized time-evolutions that
take into account possible non-standard effects leading to loss of phase
coherence and dissipation. These effects can be fully parametrized in terms of
six phenomenological constants. A detailed analysis of selected B-meson decays
shows that present and future dedicated experiments, both at colliders and
B-factories, will be able to put stringent bounds on these non-standard
parameters.
