In this master dissertation, the localization of the wireless capsule endoscopy (WCE) is studied in order to minimize the error. In particular, the influence of the different tissues of which the human body is composed and their impact on localization were analyzed. To determine the behavior of the WCE a computational model of the gastrointestinal (GI) tract and the WCE have been implemented. Moreover, a finite difference time domain solver simulation on Sim4Life has been used to study how the WCE moves through the GI tract. Four different simulations were considered, three homogeneous and one heterogeneous: one with the air model, one with fat, one with muscle, and one with a complete human body model containing all tissues.