The effects of simulated sulphuric acid rain were investigated, under controlled laboratory conditions, on the surface structure and n-alkane composition of the lichen Pseudevernia furfuracea. Thalli were collected from Larix decidua bark in a wood in a Piedmont alpine valley and treated with three concentrations of H2SO4. The response to simulated acid rain was a clear change in the quantitative alkane composition, with a decreasing trend observed for C28 and C30 with increasing sulphuric acid concentration. From a morphological point of view, a progressive reduction of the surface amorphous layer was observed as a consequence of the exposure of thalli to the acid rain treatments.