Ginger (Zingiber officinale Roscoe, Zingiberacae) is one of the most commonly used spices around the world and a traditional medicinal plant that has been widely used in Chinese, Ayurvedic and Unani-Tibb medicines for several thousand years. However, there was still lack of systemic safety evaluation. We conducted a 35-day toxicity study on ginger in rats. Both male and female rats were daily treated with ginger powder at the dosages of 500, 1000 and 2000 mg/kg body weight by a gavage method for 35 days. The results demonstrated that this chronic administration of ginger was not associated with any mortalities and abnormalities in general conditions, behavior, growth, and food and water consumption. Except for dose-related decrease in serum lactate dehydrogenase activity in males, ginger treatment induced similar hematological and blood biochemical parameters to those of controlled animals. In general, ginger treatment caused no overt organ abnormality. Only at a very high dose (2000 mg/kg), ginger led to slightly reduced absolute and relative weights of testes (by 14.4% and 11.5%, respectively). This study provides a new understanding of the toxicological properties of ginger.