Fifty-one autopsy specimens of liver were analysed for total mercury. Thirteen specimens contained less than 10 mg/kg of mercury, with a minimum value of 1.4 mg/kg, indicating that death in suspected cases was not always due to lethal exposure to methylmercury. The methylmercury concentration in 28 livers was 10-30 mg/kg. Limited additional estimations have shown that 71% of the liver mercury was organic and that the level of mercury in the liver of a 7-month-old fetus was only 25% of that in the liver of the mother. In a patient who died in hospital with a blood mercury level of 4.1 mug/ml, the liver contained 16.5 mg/kg of mercury.Differences between these results and those found in the outbreak of methylmercury poisoning in Japan are discussed. Any extrapolation of tissue mercury levels in relation to the toxic effects of methylmercury must take account of the intensity and duration of exposure.