in gallstones from 22 patients have been determined by neutron activation analysis. It is found that the concentrations of Br
Cu and Mn in " black coal cinder" - like gallstones are significantly higher than those in cholesterol and pigment gallstones by factors of 5.5- 6.9
26- 119 and 23- 76
respectively. The concentrations of iodine in some gallstones are higher than those in normal human fluid and even higher than those in thyroid in a few cases
which suggests that iodine play a role in the formation of gallstones.