The purpose of this master's thesis is to present the meaning, development and scope of the „fruits of the poisonous tree“ doctrine. The introductory part will explain the theoretical meaning and the corelation of the „fruits of the poisonous tree“ doctrine and the evidentiary barriers, i.e. exclusionary rules, which are also explained with the objective of better understanding of the subject matter. Main section of the thesis is divided into three parts. The first chapter explains the development of the „fruits of the poisonous tree doctrine“ in United States, with the particular regard to its exceptions which narrowed its scope. Second part consists of the analysis of the subject matter in the comparative law and its place in the jurisprudence of European Court of Human Rights. Third chapter of thesis is focused on the analysis of the development, acceptance and the interpretation of the „fruits of the poisonous tree doctrine“ in Croatia, with special regard to the jurisprudence of the Supreme Court of the Republic of Croatia and the Constitutional Court of the Republic of Croatia. In conclusion, the subject matter will be cosidered de lege lata and the possible de lege ferenda arrangements will be proposed, regarding its use and interpretation.