<p>Breast carcinoma is the most prevalent and lethal malignancy affecting females, and it always presents an essential healthcare problem. Doxorubicin (DOX) is a common chemotherapy utilized in treating breast carcinoma, but it also has dangerous side effects. Hence, searching for potent and safe anticancer compounds is urgent. An alkaloid, piperine, mostly found in pepper species, is a naturally occurring substance with anticancer properties. This work aims to assess the anticancer impact of piperine on breast carcinoma cells by potentially inhibiting the γ-secretase/Notch pathway, and to compare its impacts with those of DOX. The anti-proliferative effects of piperine and DOX were evaluated on various human breast carcinoma cell lines (MCF-7, T47D, and MDA-MB-231). Additionally, a flow cytometric analysis was carried out to identify the cell cycle arrest. Moreover, the protein expression levels of Notch-1, γ-secretase components, NICD, c-myc, p21, Bax, and Bcl-2 were assessed. The results demonstrated that among the tested cell lines, MDA-MB-231 cells exhibited the highest sensitivity to piperine treatment, with the lowest IC₅₀ value (32.37 ± 2.5 µM). At the G2/M phase, piperine and DOX both stopped the cell cycle. Furthermore, piperine and DOX inhibited the Notch signaling by reducing Notch-1, γ-secretase components, and NICD expression. Piperine and DOX also reduced the levels of Notch target proteins, namely, p21 and c-myc. Lastly, both drugs induced apoptosis by elevating Bax and reducing Bcl-2 expression in malignant breast cells. The promise of piperine as a targeted therapy candidate for the treatment of breast cancer is substantially supported by this research.</p> Graphical Abstract <p></p>