Since the introduction by Goodwin, Stern, Wagner and Kramer (1966) of 113Inm colloid for liver scanning, several methods of indium colloid production, based on various principles, have been brought into practice (Hisada and Mishima, 1967; Adatepe, Welch, Archer, Studer and Pochen, 1968; Bruno, Sorsdahl and Williams, 1968; French, 1969; French, Johnson and Trott, 1969; Johnson, French and Trott, 1969). In all the methods, chiefly gelatin, or occasionally dextran, has been used as a stabiliser, although both agents had already appeared unsafe as a means of stabilisation of colloidal preparations for clinical use. This is why we have introduced polyvinylpyrrolidone (PVP) as a stabiliser for 99Tcm labelled rhenium sulphide colloid (Szymendera, Malinowski, Cheguillaume and Tolwinski, 1968). Recently, Ege and Richards (1969) have also stressed that PVP is a safer stabiliser than either gelatin or dextran, while Lopez and French (1969) eliminated stabilisation of technetium colloid.