A double-blind study in which the patients and the researchers are not informed of the types of intervention or of the grouping of the patients will be conducted at the Endocrine and Metabolism Research Center and the Diabetes Unit of Shariati Hospital. Only 30-60- year old patients having type 2 diabetes with fasting blood glucose of greater than 126 mg/dl enter the project, and people suffering from hyperglycemia caused by diseases other than diabetes and patients treated with insulin are excluded from it. Sixty patients with type 2 diabetes will be divided randomly(by block randomization) into three 20-member groups receiving aqueous extract of rhubarb, alcoholic extract of rhubarb, or placebo, for 6 weeks. Similar appearance containers each containing 135 drug or placebo capsules with a special code will be delivered to the patients by the therapist of the project and the special code on each container will be recorded in the file of the related patient. Each member of the three groups will receive a container with 135 capsules, with every capsule containing 450 mg of the aqueous extract, of the alcoholic extract, or of the placebo. Each patient will take three capsules every day. The patients in all three groups are tested for the concentrations of malondialdehyde, high sensitivity C-reactive protein, fasting blood glucose, apolipoprotein B, apolipoprotein A-1, and fasting insulin at beginning and at end of the 6th week of study