This study aims to evaluate the effect of different drying methodologies (room, microwave, convective, oven and freeze-drying) on the chemical composition, the microbiological quality of extracts and the biological activities namely clotting milk and antioxidant activities for both spontaneous and cultivated Onopordum nervosum ssp. platylepis. The results showed that the drying methodology has significantly affected the phenolic composition. Freeze dried flowers showed the best amounts of total phenols, flavonoids and condensed tannins followed by the microwave dried flowers. However, the latest presented the lowest protein content. Finally, the biological activities were significantly dependent on the used drying process. The effective concentration EC50 values let to classify the samples according to their decreasing power to inhibit DPPH free radicals: dryer<oven<room <microwave<freeze-drying. The drying process significantly affected the clotting milk activity, freeze dried flowers showed the highest activity. All the obtained results do not reveal a significant difference between cultivated and spontaneous plants.