The thickness of the terminal hepatic vein wall (TTHV) and the content of perisinusoidal collagen in 989 zone 3 areas in Picro-Sirius-stained sections from 117 liver biopsies with normal morphology or slight non-specific changes were analyzed. TTHV varied from 0.4 micron to 21.3 microns (median 3.8 microns). A positive correlation was found between TTHV and the diameter of the terminal hepatic vein. The average TTHV of the individual biopsies was not correlated to age, sex or liver morphology. The average zone 3 collagen content did not exceed that of zones 2 and 1, with the exception of biopsies with slight steatosis, where a minimal increase in zone 3 collagen was found. The normal variability of TTHV and the correlation to the diameter of THV must be considered in the evaluation of perivenular fibrosis. Even a slight increase in perisinusoidal collagen content may be suggestive of a pathological condition.