In this study, the role of acetylsalicylic acid (ASA) pre-treatment (1 or 10 mu M) in inducing salt and osmotic tolerance was investigated in a wild species of potato (Solanum acaule) using NaCl (80 mM) and polyethylene glycol (15% PEG 6000) in vitro. Salt stress had no negative effect on growth parameters and photosynthetic pigments. Lipid peroxidation, electrolyte leakage. H2O2 content and lipoxygenase (LOX) activity remained unaffected, but the activity of superoxide dismutase (SOD), guaiacol peroxidase (GPOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) was enhanced by salt stress. On the contrary, PEG decreased growth parameters and photosynthetic pigments and increased oxidative stress and all antioxidant enzymes activity. However, ASA pre-treatment, especially at 1 mu M, improved growth parameters and photosynthetic pigments, reduced lipid peroxidation, electrolyte leakage, H2O2 content and LOX activity and enhanced the activity of SOD, GPOD, APX, CAT and GR enzymes under stresses and to a lesser extend under non-stress conditions. Pre-treatment of ASA appeared to induce preadaptive responses to salt and water stresses leading to promote protective reactions to the photosynthetic pigments and maintain the membranes integrity in this wild species of potato, which were reflected in improving the plant growth.