© 2022, The Author(s) under exclusive licence to Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.Terricolous lichens, located in soils, can change the bioavailability of polluted soil biologically, chemically and physically with their effective enzymatic content. Their effects are unknown especially on weathered p,p'-DDE-contaminated soil. However, we obtain new information by increasing our studies on this subject. In the present study, the impact of Peltigera praetextata (a terricolous lichen) on zucchini (Cucurbita pepo spp. pepo) grown in weathered p,p'-DDE-contaminated soil was shown via its physiological responses. At the same time, the physiological responses of Peltigera praetextata were also given. The results show that the growth and development of the zucchini grown in weathered p,p'-DDE-contaminated soil was positively affected by Peltigera praetextata. Peltigera praetextata was increased the bio-usefulness of weathered p,p'-DDE-contaminated soil with its effective enzyme contents. Moreover, Peltigera praetextata was able to cope with p,p'-DDE contamination with the strong antioxidative defence system.