A simple multidisciplinary and inexpensive laboratory exercise is proposed, in which the undergraduate student may correlate biochemical and anatomical findings. The entire practical session can be completed in one 2.5-3 hour laboratory period, and consists of the quantification of collagen and total protein content from tissue sections--without previous homogenisation--by a colorimetric assay, and a staining method for in situ collagen detection carried out on the same tissue samples using the same chemicals. Because collagen accumulation is a common characteristic of hepatic diseases such as fibrosis and cirrhosis, the experiment may also serve as the basis for discussing the importance of collagen detection and quantification in estimating the degree of fibrosis from subjects with liver disease. (Contains 2 figures and 4 tables.)