Ten Type 2 diabetic patients with moderately hyperglycemia, received a raw extract of Cucurbita ficifolia or potable water in a single dose of 4 ml/Kg body weight, in two different sessions at least separated by 1 week. Blood glucose levels were followed in both parts of the study by a period of 5 h. The patients had stopped their pharmacologic medication 24 h prior to each part of the study. As expected, no significant changes on blood glucose were observed after giving the vehicle; however, the oral administration of C. ficifolia was followed by a significant decrease in blood glucose levels, from 12.07+/-1.69 mM (217.2+/-30.4 mg/dl) to 9.42+/-1.96 mM (169.6+/-35.3 mg/dl) 3 h after and to 8.37+/-1.74 mM (150.8+/-31.3 mg/dl) 5 h after the extract administration. The hypoglycemic action of Cucurbita ficifolia agrees with its effects previously observed in laboratory animals. The results of this preliminary study do not give indications for the mechanism of this hypoglycemic effect.