A number of circulating breakdown products of collagen or other components of extracellular matrix, matrix degrading metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been proposed as markers of hepatic fibrosis. However, the published results lack consistency. Since many of the patients with fibrosis studied were alcoholics, the question was raised whether recent alcohol consumption may affect the results obtained. Using sandwich-type assays of radioimmunoassay technology with corresponding antibodies, we studied eight markers of liver fibrosis: laminin, tenascin, undulin, TIMP-1, collagen VI, procollagen type III (PIIINP), hyaluronic acid (HA) and MMP-2. A group of 10 alcoholics was studied after significant alcohol consumption and following 2 weeks of abstinence, verified with repeated breath alcohol measurement. Laminin was significantly reduced at 1 week (22%) and at 2 weeks (30%). Similarly, tenascin and undulin were also significantly decreased. By contrast, TIMP-1, collagen VI, PIIINP, HA and MMP-2 did not significantly change. The mode of action of alcohol on these tests is unknown. These differences must be considered when using those measurements to assess liver fibrosis.