In Quran, the great, Surah Baghareh, Verse 255, it is stated: “Who is he aware of everything and the limited knowledge of humankind originates in His unending and unlimited knowledge”. One of these sciences is the science of Pharmaceutical plants. Recognizing these plants plays an important role in the improvement of human society health. Herbal therapy is one of the supplement methods for improving the health rate. In Al-Rahman, verse 11, the significance of plants and fruits is mentioned. One of the mentioned plants is Urtica dioica, which is anti-diabetic. Objectives: The objective of this study is to determine the protective effect of extract of Urtica dioica leaf on small intestine structure in order to find its anti-diabetic effect. Materials and Methods: At first, the rats were injected 50 kg. Mg-1of Streptozotocin via their tail vane. The fasting animals with more than 250 mg dl-1 blood sugar were diagnosed as diabetic. One diabetic group was under therapy of blue extract of Urtica dioica leaf (daily injection of 4 cc kg -1 in Peritoneum). The blood sample and tissue of the intestine were prepared after two months of therapy and killing animals. The Histologist saw the samples tissue. The quality of parameters of tissue was assessed in both the therapeutic and non-therapeutic groups. Results: The blood sugar decreased from 400 ± 54.2 mg dl -1 to 78.9 ± 11.9 dl (P > 0.0004) in therapeutic group while the blood sugar was not found in diabetic group. The mononuclear cells and destructive tissues were found in necrosis and infiltration of diabetic group, also epithelium and Lieberkuhn glands were destructed and the villain became short and atrophy 9 and the high level of blood shedding and exudate were found. In contrast, necrosis was not found in therapeutic group and infiltration of mononuclear cells and inflammation tissues were found slightly. There were not shorted villain and atrophy. Consuming Urtica dioica prevents the intestinal side effects of diabetes. Conclusions: Urtica dioica protects the mucosa of small intestine. This may lead to recovery of blood transfusion with decreasing end product mechanism (Advanced glycosylation end product) or improving the function of the nervous system by decreasing Sorbitol production. Further studies are needed for determining the major mechanisms.