In recent years all over the world, medicinal plants are used quite a lot but side effects of biological and chemical contents and radiopharmaceutical interactions for each consumer in question aren't entirely well-known. The studies of plant origin drug interaction with radiopharmaceuticals are highly relevant and desired. One of them is passiflora syrup (Passiflora incarnata L., Passifloraceae) which is widely used for depression, insomnia, anxiety and menopause period. The aim of current study is to evaluate possible effects of passiflora syrup on the biodistribution of Tc-99m-DTPA and its blood cells uptake. DTPA was labeled with Tc-99m radionuclide. Biodistribution studies were performed on male Wistar albino rats which were treated via oral feeding-gavage-method with either passiflora syrup or 0.9 % NaCl as control group for ten days. Blood samples were obtained by cardiac blood withdrawal from the rats and they were radiolabeled. The biodistribution results showed that the passiflora syrup decreased the uptake of Tc-99m-DTPA in kidneys and in blood cells. Tc-99m-DTPA being used widely as a kidney diagnostic agent in nuclear medicine seems to be interacting with orally taken passiflora. Passiflora syrup may modify the uptake of Tc-99m-DTPA by kidney. The knowledge of this negative effect may contribute to reduce the risk of misdiagnosis and/or repetition of the examinations in nuclear medicine.