Effervescent or carbon tablets are tablets which are designed to dissolve in water, and release

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

. They are products of compression of component ingredients in the form of powders into a dense mass, which is packaged in

blister pack A blister pack is any of several types of pre-formed plastic packaging used for small consumer goods, foods, and for pharmaceuticals. The primary component of a blister pack is a cavity or pocket made from a formable web, usually a thermofor ...

, or with a hermetically sealed package with incorporated

desiccant A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants ...

in the cap. To use them, they are dropped into water to make a solution. The powdered ingredients are also packaged and sold as effervescent powders or may be granulated and sold as effervescent granules. Generally powdered ingredients are first granularized before being made into tablets. Effervescent medicinal beverages date back to the late 1800s and originally arose to mask the taste of bitter waters taken as curatives, during the

water cure Water cure may refer to: * Water cure (therapy), a course of medical treatment by hydrotherapy * Water cure (torture), a form of torture in which a person is forced to drink large quantities of water * ''The Water Cure ''The Water Cure'' is ...

craze of that era.

History

In the 17th and 18th centuries, scientists began uncovering the chemical make-up and physiological benefits of various salts such as

Glauber's salt Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 mill ...

and

Epsom salts Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is