The current article reports the in vitro biological activities and phytochemical studies using aqueous methanolic extract in plants fractions of Inula viscosa (I. viscosa). The plants were collected from the region of Algerian Kabylia in the wilaya of Bejaia. The phytochemical studies of the leaves of I. viscosa showed that the fraction of the plant extract proves as an active agent that can be used as an antioxidant or antileishmanial agent. Initially, the extract was prepared using aqueous methanol and then fractionated with ethyl acetate and butanol solvents. Total phenolic compounds, tannins, and flavonoids, of the hydromethanolic extract and their fractions were determined by the Folin-Cioalteu method, respectively, in gallic acid equivalent and aluminum chloride in rutin equivalent. The plants with their fractions were tested using the agar diffusion method for antimicrobial and antiparasitic activities against common bacteria (two visceral and skin Leishmania). Antioxidant activities were carried out using phosphomolybdenum, FRAP, and DPPH tests. Experimental results showed that the plant extract and fractions were rich in phenolic compounds and exhibited potent antioxidant, antimicrobial, and potency for moderate antileishmania activity. It was concluded that the plant I. viscosa is a promising medicinal plant.