The Total Antioxidant Capacity of several human fluids was compared and the following sequence of TAC values was found: urine > saliva > blood plasma > milk ≈ amniotic fluid >> sweat. Lower TAC values were found for the saliva of smokers than for that of non-smokers. Drinking of a cup of instant coffee increased the hydrogen peroxide content of urine but did not decrease the TAC of urine.