The purpose of this test is to evaluate the potential of medical devices, cosmetics, drug candidate chemicals, and natural substances to cause systemic adverse reactions. In the subacute toxicity experiment, in which experimental animals are exposed to the test substance for 28 days, general effects, as well as organ and organ system effects, may occur as a result of the absorption, distribution and metabolism of substances from the device or the material of which the device is made to parts of the body that do not directly contact them. Although these visible effects result from systemic absorption and distribution of toxic substances, this test assesses overall systemic toxicity, not specific target organ or organ system toxicity. As a result of these tests, the doses to be selected for use in subchronic toxicity tests are determined.