Many organs and systems, especially the kidney, are damaged by the effect of high-dose cadmium. These functional problems vary depending on the distribution of cadmium in the body, the way it is taken, the dose and the duration. Antioxidant activities of algae are due to the polyphenols, polysaccharides, pigments and vitamins they contain. Antioxidants are effective in protecting the body against damage caused by reactive oxygen species. This study was carried out to determine the therapeutic effects of Ulva rigida extract on kidney tissue fibrosis, inflammatory inflammation and apoptosis in cadmium-induced rats. In the study, 1 mg/kg CdCl₂ was injected subcutaneously to the subjects four times a week for one month (G2). Concurrently, 50 mg/kg (G3) and 100 mg/kg (G4) algae extract were given to the subjects by gavage. In staining with hematoxylin-eosin, mononuclear cell infiltration in the kidney tissues, dilatation in the tubules, shrinkage of the glomeruli and degeneration of epithelium occurred with the induction of Cd. Immunohistochemically, it was determined that TGF-β, TNF-α and NF-kB immunoreactivity was high due to tubular cells undergoing inflammation and apoptosis. Histopathological data show that U. rigida extract has a protective role against kidney damage in Cd-induced rats. Algae extract was found to play a protective role against cadmium-induced kidney damage. It was also found to have an important role as a therapeutic agent against oxidative stress.