A term applied in naturopathic, Eclectic, and Thomsonian medicine to those plants or procedures that stimulate changes of a defensive or healing nature in metabolism or tissue function when there is chronic or acute diseases. The whole concept of alteratives is based on the premise that in a normally healthy person, disease symptoms are the external signs of activated internal defences and, as such, should be stimulated and not suppressed. Sambucus (Elder), as an example, acts as an alterative when it is used to stimulate sweating in a fevered state. Without a fever or physical exertion, Sambucus tea will increase intestinal, lung, and kidney secretions. With fever or exercise, the buildup of heat from combustion, and the dilation of peripheral blood supply, it takes the defence response to the next stage of breaking a sweat. You might have sweated eventually anyway, but you may be one of those people who doesn't perspire easily, and a diaphoretic such as Sambucus will act as an alterative for you by stimulating the next stage of defences sooner than you would have on your own. The term alterative is sometimes inaccurately used as a synonym for "blood purifier," particularly by nature-cure neo-Thomsonians such as Jethro Kloss and John Christopher. "Blood purifier" is a term better applied to the liver, spleen, and kidneys, not to some dried plant.