OBJECTIVE To investigate whether the acid suppression therapy influences the absorption of bismuth from colloidal bismuth subcitrate (CBS); to locate the deposit position of bismuth in mice's organs and to detect the consequential change of cell functions in these deposited organs. METHODS 48 male SD rats weighing from 200-250 g were randomly divided into five groups: Group A(1), kill the rats on the cessation day of administration CBS; Group B(1), kill the rats on the day 8 weeks after the cessation of administration CBS; Group A(2) (CBS + amoxicillin + metronidazole + omeprazole), kill the rats on the cessation day of administration; Group B(2) (CBS + amoxicillin + metronidazole + omeprazole), kill the rats on the day 8 weeks after the cessation of administration; Control group. These medicines had been taken every day for 14 days. The issue sections (liver, brain and kidney) were counterstained after AMG development. The bismuth deposited in tissues was observed by microscopy. At the same time, the gray level of kidney tissue sections were measured and compared through image processing program. The deposition of bismuth and the degrees of cell organ's impairment were observed through electron microscopy. By the use of electron probe microanalysis, bismuth can be distinguished from chemical element. RESULTS The bismuth can be accumulated in cell bodies of proximal convoluted renal tubule, portal area, hypothalamus, and hypoglossal nuclei after its absorption. Under the light microscopy, heavy AMG staining granules were found in cell bodies of proximal convoluted renal tubule. It was discovered that the amounts of bismuth accumulation in kidney of quadruple therapy group were much more than that of single compound therapy group (P < 0.05). The amounts of bismuth accumulation in kidney on the cessation day of administration are more than that 8 weeks later (P < 0.01). What is more, under the electron microscopy, heavy AMG staining granules were found exclusively in lysosomes of proximal convoluted renal tubule cell. The electron microscopy found some cell impairment in quadruple therapy group: the impairment to these cells can be recovered 8 weeks after the cessation of administration. CONCLUSIONS The acid suppression therapy causes an increase of bismuth absorption and accumulation from CBS in the rats' kidney. Finally, the absorbed bismuth can be discharged out of the body via kidney. Large amounts of bismuth accumulation in kidney can impair the functions of proximal convoluted renal tubule cell.