This study investigates the phytochemical profile and in vitro antioxidant activity of the aqueous extract of Hedera algeriensis (AEHa), as well as its hepatoprotective effects in vivo against oxidative stress and liver damage induced by ovalbumin (OVA) sensitization in a rat model of allergic inflammation. The bioactive compounds (total polyphenols, total flavonoids, and condensed tannins) and antioxidant activities (DPPH, FRAP, TAC) of AEHa were analyzed. Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize its phytochemical profile. Twenty-four male Wistar rats were divided into four groups: Group 1 (Control): rats receiving no treatment, Group 2 (OVA sensitized): rats receiving OVA, Group 3 (AEHa): rats treated with AEHa at a dose of 500 mg/kg by gavage, and Group 4 (OVA+AEHa): OVA-sensitized rats treated with AEHa. Serum biochemical parameters, oxidative stress markers, and liver histology were evaluated. The phytochemical analysis revealed that AEHa was rich in polyphenolic compounds and exhibited significant antioxidant activity. FTIR analysis identified various chemical functional groups in AEHa, indicating its richness in bioactive compounds. Furthermore, AEHa administration effectively protected against OVA induced liver dysfunction by reducing the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), albumin, and globulin. Additionally, AEHa decreased malondialdehyde (MDA), nitric oxide (NO), and advanced oxidation protein products (AOPP), while increasing levels of reduced glutathione (GSH), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPX), and catalase, and improving liver histology. These findings suggest that the bioactive compounds in Hedera algeriensis provide antioxidant and hepatoprotective effects. Therefore, this plant could serve as a source of bioactive natural products, potentially initiating new pharmaceutical research.