Giant taro (Alocasia macrorrhiza (L.) Schott), is a perennial ornamental plant. In this study, nine new (1-9) and six known (10-15) piperidine alkaloids were obtained from the rhizomes of A. macrorrhiza. The chemical structures and absolute configurations were established utilizing a variety of spectroscopic techniques, Mosher, Snatzke method and single-crystal X-ray crystallography. The isolates were evaluated for their antiproliferative activity on SGC-7901, MDA-MB-231, HepG2, K562, CNE2, SPC-A-1, HeLa, A-375 and Hacat cells. The results revealed that piperidine alkaloids exhibited significant antiproliferative activity against these tumor cells, with a particularly pronounced effect on K562 cells.