The effects of oral administration of guaiacolic ester of acetyl salicilic acid in 24 patients with chronic obstructive lung disease have been evaluated. 1.5 g of this drug were given daily into 3 administrations improving both objective and subjective symptomatology in 19 of the 24 patients after 1 or 3 weeks of treatment. Moreover, a statistically significant improvement of FEV 1" (p less than 0.001), Raw (p less than 0.005) and FEV 1"/VC (p less than 0.01) was observed. The remaining 5 patients discontinued the treatment failing the improvement of the subjective symptomatology.