The atmospheres of stars orbiting around black holes/neutron stars may contain a large amount of α and r-process elements as a result of contamination with the nucleosynthesis products in the matter ejected during any supernovae event associated to the formation of the compact object. The discovery of a strong overabundance of α-elements in the atmosphere of the companion in the massive black hole binary GRO J1655-40 has provided an unique way to establish the mass of the progenitor. Spectroscopy of other secondaries of selected LMXBs is crucial to establish an empirical relationship between the masses of black holes/neutron stars and those of their progenitors while the observations of radioactive elements can also provide a datation of any supernova event. Among the remarkable results provided by UVES at VLT is certainly the measurement of the isotopic ratio of lithium in several metal-poor stars. The presence of 6Li in the early Galaxy is difficult to explain, one should be however aware of the uncertainty of this measurement, especially in presence of the line asymmetries induced by convective motions.