To dilute solutions (usually 0.1 mM) of heavy metal ions were added bile acid anions in concentration varying from 0.1 to 80mM and changes in polarographic limiting currents and half-wave potentials were followed. The concentration of free metal ions can be measured by polarography even in turbid solutions, containing small aggregates, colloids and suspended material. In 1mM or more dilute solutions monomeric anions do not interact with ions of divalent metals ( Cu²⁺, Cd²⁺, Pb²⁺, Fe²⁺ and Zn²⁺). At concentrations between 1 and 10mM small aggregates of bile salts are formed, yielding complexes of limited solubility. At concentrations above about 20mM larger aggregates are formed that form more soluble complexes, due to hydrophilic character of excessive free COO^- groups. Presence of COO^- is essential for the interaction with Me²⁺: taurocholate, having an SO₃^- group in the chain in position 17, shows no interaction with Me²⁺. Solubility of compounds formed decreases in the sequence: Cu²⁺ > Cd²⁺, Zn²⁺ > Pb²⁺ and depends on the number, position, and stereochemistry of steroid OH groups in bile salt molecules, that affect differences in stacking. Increase in ionic strength results in lower stability of the complex formed. Increase in initial concentration of the metal ion results in a shift of the range in concentration of bite salt at which the complex is formed to lower concentration of bile acid salt. Simultaneously the solubility of the slightly soluble complexes decreases, as corresponds to a practically constant solubility product.