When a poison contacts a tissue and a chemical action occurs, the poison will produce an injury to that tissue. The effects of an exposure to a poison, however, will differ based on the poison involved, the type of exposure, and the method of exposure to any given poison: immediate, long-term, and etiologic. Immediate effects depend on the dosage received by the person exposed to the poison. Dosages can be large or small, short-term or long-term, and can be acute, subacute, or chronic. Effects from the type of exposure can vary from none, to slight discomfort, to illness, and even death. Effects may also depend on the person exposed.