Diabetes is one of the most common endocrine metabolic disorders. Dual endocrine deficits of impaired insulin action and inadequate insulin secretion create an environment of chronic hyperglycemia and general metabolic disorders. Nowadays, herbal drugs are gaining popularity in the treatment of diabetes and its complications. The major merits of herbal medicines seem to be their efficacy, low incidence of side effects and low cost. In the Northeast region of Brazil, Xingó, it is found a tree named Parkinsonia aculeata (Cesalpinaceae) which is used in the popular medicine as an anti-diabetic agent. In this work were evaluated the serum and urinary glucose, hepatic glycogen, serum cholesterol, triglycerides and HDL-cholesterol, in a groups of alloxan-induced diabetic rats (150 mg/Kg; ip), treated for 16 days with P.aculeata aqueous fraction extract (125 mg/Kg and 250 mg/Kg body weight). Aerial parts of the plant were powdered and extract made following a scale of polarity: first by ethylic ether, then chloroform, ketona, and finally distilled water (the aqueous fraction extract). To validate the experimental model, a diabetic group treated with insulin was adopted. Positive and significant results were found in serum and urinary glucose, hepatic glycogen, serum cholesterol, triglycerides and HDL-cholesterol, in alloxan-induced diabetic rats when using boyh doses of P.aculeata aqueous fraction extract. Our results suggests that the aqueous fraction of P. aculeata extract has a considerable effect in the carbohydrate and lipids metabolism parameters evaluated in alloxan-induced diabetic rats.