Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation. Because of its hygroscopic nature, anhydrous calcium chloride must be kept in tightly-sealed air-tight containers.

For desiccant uses, drying tubes are frequently packed with calcium chloride. Adding solid Calcium Chloride to liquids can remove dissolved water. Calcium chloride is also used in products as an air moisture absorber. These hygroscopic properties are also applied to keep a liquid layer on the surface of the roadway, which holds dust down.

For deicing and freezing point depression uses, by depressing the freezing-point, Calcium Chloride is used to prevent ice formation and to deice. This is particularly useful on road surfaces.

Calcium Chloride is used to increase the hardness in swimming pools. This reduces the erosion of the concrete in the pool. Increasing the concentration of calcium in the water, will reduce the dissolution of calcium compounds essential to the structure of concrete.

In marine aquariums, Calcium Chloride is added to introduce bioavailable calcium for calcium carbonate shelled animals such as mollusks and cnidarians. Calcium hydroxide (kalkwasser mix) or a calcium reactor can also be used to introduce calcium, however calcium chloride addition is the fastest method and has minimal impact on pH.

For food industry, Calcium Chloride is used in canned vegetables, in firming soy bean curds into tofu and in producing a caviar substitute from vegetable or fruit juices. It is commonly used as an electrolyte in sports drinks. The extremely salty taste of calcium chloride is used to flavor pickles while not increasing the food's sodium content.

In brewing beer, Calcium Chloride is sometimes used to correct mineral deficiencies in the brewing water. It affects flavor and chemical reactions during the brewing process, and can also affect yeast function during fermentation. It is sometimes added to processed milk to restore the natural balance between calcium and protein in casein for the purposes of making cheese.

For medicine uses, Calcium Chloride can be injected as intravenous therapy for the treatment of hypocalcaemia. It can be used for insect bites or stings; sensitivity reactions, particularly when characterized by urticaria; magnesium intoxication; as an aid in management of the acute symptoms in lead colic; and in cardiac resuscitation, particularly after open heart surgery. It can help to protect the myocardium from dangerously high levels of serum potassium in hyperkalemia. Calcium chloride can be used to quickly treat Calcium Channel Blocker toxicity.