The hawthorn fruit, a member of the Rosaceae family, is a medicinal plant with numerous therapeutic properties. It has a wide range of variants, with Crataegus tanacetifolia being the most widely recognized species in the world. The hawthorn fruit has various biological activities, including anti-inflammatory, antibacterial, antioxidant, immune-modulating, and anti-carcinogenic properties. This study focused on improving the antioxidant activity of hawthorn vinegar via different methods. We also aimed to investigate the influence of its hepatic antioxidant abilities on health and extend the shelf life of the vinegar. In the study, the vinegar was produced from the hawthorn fruit, and thermal pasteurization and ultrasound techniques were applied. A total of 56 female adult Wistar-Albino rats were allocated into seven groups and administered hawthorn fruit vinegar via oral gavage on a daily basis. The experimental groups included rats treated with pasteurized vinegar (HVP), ultrasound-treated rats (HVU), and an untreated group that received regular vinegar (HVN) at two different dosage levels (0.5 and 1 mL/kg). The SOD, MDA, and CAT antioxidant levels were measured using the ELISA method in plasma and liver tissue samples. The total plasma cholesterol, triglyceride, HDL, LDL, AST, and ALT values were quantified using commercially available kits. The levels of SOD and CAT in the plasma and liver were found to be significantly higher in the HVU1 group compared to all other groups. Furthermore, the HVU1 cohort exhibited the highest HDL value in plasma. The plasma LDL levels were comparably low in both the thermal-pasteurized and ultrasound-treated groups. There were significant expressions of both CAT and SOD in the liver tissues of the HVU groups (analyzed immunohistochemically). These results indicated that hawthorn vinegar administration with 1 mL/kg in group HVU1 could significantly enhance antioxidant capacity in the liver and, consequently, overall health. It can be suggested that the possible therapeutic effects of hawthorn vinegar may boost its antioxidant capabilities and contribute to an overall improvement in quality of life.