Diabetes mellitus (DM) is a metabolic disease with 2.8% incidence worldwide. Insulin dependent DM (IDDM) or type I DM, usually arising in early ages, in most cases is accompanied by complications on vital organs like, kidney and heart. Medemia argun (MA) is an Egyptian palm, rich in proanthocyanidins (PACs), which are beneficial against a wide variety of human ailments. Thirty male rats were classified into 5 equal groups (6 rats each). Type I DM was induced by a single intraperitoneal (IP) injection of alloxan (120mg/kg). Rats were then treated by insulin (30 U/kg, daily), MA seed ethanolic extract (100mg/kg, orally, once daily, dissolved in sterile saline) for one week. Random blood sugar (RBS), serum creatinine, urea, triglycerides, total cholesterol, both high and low density lipoprotein cholesterol (HDLC, LDLC) and pancreatic tissue morphology were studied. MA showed insulin-mimetic action by significant downregulation of RBS, more significantly when given with insulin. This action was accompanied by preserving the populations of pancreatic beta, alpha and delta cells, usually perturbed by DM induction. Similarly, MA protected kidney through maintaining creatinine and urea normal levels. The effect of MA on lipid profile members was conflicting, as showing increments in triglycerides, total cholesterol and LDLC, with decreased HDL-C, compared to diabetic animals. Oral administration of MA ameliorated DM through showing preservation of pancreatic tissue and improving kidney functions. It protected DM subjects against complications on both pancreatic and kidney tissues, although it hasn't a promising value in the protection of cardiovascular system which showed disturbed lipid profile.