Vertebrate coprolites derived from the Upper Triassic terrestrial deposits of southern Poland have been subjected for various analytical methods in order to retrieve the information about their composition, potential producer's diet and nature of the preserved microbial structures. Morphologically, they have been classified to four morphotypes, of which only three were further analysed due to their good state of preservation. Their groundmass occurred to be composed by francolite, a carbonate-rich apatite, in which abundant coccoid structures are preserved. Based on various microscopic and organic geochemical techniques, they are interpreted as fossilized bacteria which could have mediated the phosphatization of the faeces. The thin sectioning revealed that the coprolites consist of those containing exclusively bone remains, and those preserving both bone and plant remains. Those coprolites preserving only vertebrate remains are suggestive for exclusive carnivorous diet of the producers. However, the interpretation of coprolites consisting of both vertebrate and plant remains is more debatable. Although they may attest for omnivory, it is not excluded that potential producers were carnivorous which occasionally ingested plants, or accidentally swallowed plant material during feeding. The latter may involve predation or scavenging upon other herbivorous animals which used to fed on plants. It is not excluded that the potential producers may have been animals that foraged in or near aquatic habitats, such as semi-aquatic archosaurs and/or temnospondyls, what is supported by the presence of ostracode remain and fish scales within the coprolites, as well as by the presence of such specific biomarkers as phytanic and pristanic acids, which are characteristic constituents of fish oil. The preservation of such labile organic compounds as sterols, palmitin, stearin or levoglucosan attests for mineralization of the faeces on very early stages of diagenesis.