Ceratonia siliqua, commonly called carob tree or locust beans, is a flowering evergreen tree in the family Fabaceae. It is native to the Mediterranean region, including southern Europe, northern Africa, and western Asia. It has a long history of use for both food and medicine. The ripe pods are edible and often ground into carob powder to substitute for cocoa powder. Carob tastes sweet and is used in powder, chip, or syrup as food ingredients. Medicinally, it treats diarrhea, obesity, vomiting, and high cholesterol.

Carob pods contain lots of polyphenols, especially tannins. The tannin composition of carob wood was chemically analyzed to show principal amounts of gallotannins and proanthocyanidins, suggesting various benefits. Acetone and methanol extracts of it also showed anti-bacterial activities against phytopathogenic bacteria. The mechanism is still unknown, but one of the phytoalexins, solavetivone, might be responsible for the protective effect. Recently, tyrosinase-inhibiting activity by the bark extract of carob tree was reported, and the clinical study confirmed its skin-brightening effect.