Nowadays, many medical techniques apply electromagnetic fields (EMF) on patients with therapeutic and/or diagnostic purposes. For this reason, to provide safe and effective treatments, it is necessary to comprehend the mechanisms of interaction between the biological system under exposure and the applied EMF. This interaction is described by the dielectric properties of the considered system. Biological tissues are complex and heterogeneous, and their dielectric properties change with frequency and under the influence of many factors. In particular, at frequencies higher than 1 GHz the main influence on the dielectric behaviour of a certain tissue is given by its water content. In this work, an approach is proposed for the reconstruction of the dielectric properties of biological tissues from their water content. An experimental validation is given on muscle and liver ex-vivo animal samples whose water content is measured through the desiccation technique.