Ginseng is a well-known traditional medicine used in Asian countries for several thousand years, and it is currently applied to medicine, cosmetics, and nutritional supplements due to its many healing and energygiving properties. It is well demonstrated that ginsenosides, the main ingredient of ginseng, produce a variety of pharmacological and therapeutic effects on central nerve system (CNS) disorders, cardiovascular disease, endocrine secretions, aging, and immune function. Korean red ginseng extract is a dietary supplement containing ginsenoside Rb1 and ginsenoside Rg1 extracted from Panax ginseng. While the pharmacokinetics and bioavailability of the extract have been well established, its toxicological properties remain obscure. Thus, four-week oral toxicity studies in rats were conducted to investigate whether Korean red ginseng extract could have a potential toxicity to humans. The test article was administered once daily by oral gavage to four groups of male and female Sprague-Dawley (SD) rats at dose levels of 0, 500, 1,000, and 2,000 mg/kg/day for four weeks. Neither deaths nor clinical symptoms were observed in any group during the experiment. Furthermore, no abnormalities in body weight, food consumption, ophthalmology, urinalysis, hematology, serum biochemistry, gross findings, organ weights, or histopathology were revealed related to the administration of the test article in either sex of any dosed group. Therefore, a target organ was not determined in this study, and the no observed adverse effect level (NOAEL) of Korean red ginseng extract was established to be 2,000 mg/kg/day.