The results of radiochemical purity measurements for99mTc–S colloid, 90.7±1.4, and99mTc–Sn colloid, 98.9±1.2 obtained by ITLC (SG) with 80% methanol are given. The range of biodistribution normal values for99mTc colloid preparations for animal organs is determined. The results of99mTc–S and99mTc–Sn colloid distribution in liver are 95.4±6.1% and 100,0±5.4%, respectively.