Using the VLT we have obtained high quality spectra of about 70 high redshift (1- 4.6) galaxies within the FORS Deep Field (FDF). As expected most of them turn out to be (bright) starburst galaxies and the observed spectra agree with synthetic ones. The equivalent width of the CIV(1550) absorption line turns out to be a good indicator for the galaxies metallicity. Furthermore our high-z starburst galaxies show increasing metal content with decreasing redshift. Compared with local starburst galaxies they tend to be overliminous for their metallicity.