The fruit of the carob tree, has been used since ancient times to feed livestock in its place of origin, the Mediterranean, given the fertility of this tree: a single specimen can produce up to 600 kilos of carob pods per year. Its generic name comes from the Greek keraton, 'horn' referring to the peculiar shape of its fruit. The outside of the fruit without seeds, has astringent, while seeds are laxatives. In North Africa these legumes are used in the preparation of syrups. The seeds of this humble tree were used in the Middle Ages as a unit of weight for the trade of precious stones and metals. The word carat, which comes from the Arabic querat, originally referred to the weight of a carob seed. Al-Andalus was a door to Europe for the gold from Sudan, hence the diffusion of the same term.