Abstract
            Introduction: Hypericum perforatum consists of several biologically active compounds that  may affect cell physiology.  
  Objectives: This study attempted to estimate the effect and safety of a tea that was prepared  from H. perforatum on renal histology and function.  
  Materials and Methods: A double-blind controlled experimental trial was conducted on  25 male rats. These animals were divided into four groups. Three of them were labeled as  the study groups, and each consisted of seven animals. The fourth group was labeled as the  control group consisting of four animals that lived in the same environment and consumed  the same food as the other groups. The animals in each study group consumed a prepared tea  with a different concentration for each group. The herbal tea of H. perforatum was made as  recommended by the local traditional preparation method. Doses of 3, 6, and 9 cc/kg/d were  calculated and selected according to the recommendation. Each of these doses was given to  each group of the experiment for four weeks mixed with water.  
  Results: A slight increase in blood urea and serum creatinine and a decrease in serum  albumin levels were noticed in the experimental groups compared to the control group. In  addition, the weight of the kidneys in the study groups was more than the control group.  There were microscopical changes in the renal histology that was noticed in the higher doses  of H. perforatum tea.  
  Conclusion: Higher doses of H. perforatum tea can induce damage to the renal tissue.