The study was performed as a double-blind clinical trial to examine the effect of Apium graveolens L on the blood glucose in type 2 diabetic patients who referred to the diabetic treatment research center of Yazd. 74 patients diagnosed with diabetes type 2 with the age range of 20-80 are randomly selected and categorized into two groups. The patients do not take insulin, non-conventional medical products, and medicines including Aspirin, Warfarin, Clopidogrel, diuretics and Thyroid drugs as well as they are not pregnant and lactating. In the main group, in addition to their standard treatment, FBS, 2HPP, and HbA1C are measured before they start taking the capsules. Then, if the patients do not need to take insulin and are satisfied to participate and also considering the number of their oral medicines and HbA1C, they are enrolled in the study. Subsequently, along with their standard treatment, the patients take three capsules containing celery fruits per day, half an hour before a meal, within three months. After three months, the blood tests are repeated and FBS, 2HPP, and HbA1C are measured again. In the control group, the same procedure is done using placebo containing cellulose. Finally, the results of the two groups are compared together.