The objective of this work is to investigate the hypoglycemic effect of 12 "antidiabetic" plants used in Mexico. The studies were performed using 27 healthy rabbits with the gastric administration of water, tolbutamide or decoction of the "antidiabetic" plant before the induction of temporary hyperglycemia by subcutaneous injection of 50% dextrose solution (4 ml/kg of weight) at the beginning of the experiment and after 60 min. Blood glucose was determined every 60 min for a period of 5 h. Tolbutamide and eight of the studied plants decreased significantly the hyperglycemia as compared with control test (water) (p < 0.05). The strongest effect was yielded by Guaiacum coulteri, followed by Marrubium vulgare, Crataegus pubescens, Cynodon dactylon, Calea zacatechichi, Buddleia americana, Bauhinia divaricata and Coix lachryma. The decrease of hyperglycemia caused by Physalis phyladelphyca, Pavonia schiedeana and Eucaliptus globulus was not significant (p > 0.05). Urtica dioica increased glycemia slightly.