Adult human body contains 1.5 g of cobalt, accumulated mainly in the liver. The elimination half-life has not been established. The cobalt concentration in the blood depends on the season and time of day, which is associated with the nutrition peculiarities. Cobalt excess is excreted through the kidneys (86 %) and intestines (14 %). Cobalt deficiency has been described in animals, but there are no reliable data on cobalt deficiency in humans. According to some scientists, cobalt deficiency corresponds to vitamin B12 deficiency. Determination of cobalt concentration in blood in clinical medicine is used to detect intoxication, not deficiency.