The biological effects of polysaccharides in vitro are strongly related with their chemical structure and frequently with the cell. In this study, we investigated the effects of two distinct polysaccharides on primary macrophages, the RAW 264.7 cell line, and the HeLa tumor cells. The acid heteropolysaccharide from the exudate of the fruit of Chorisia speciosa (PEP) did not affect the viability of peritoneal macrophages after 48 h of treatment, but decreased the viability of RAW 264.7 macrophages (50-100 µg/mL), while interestingly also promoted its growth after 48 h. PEP had little toxicity to HeLa cells, and affected its proliferation independently of concentration. The neutral xyloglucan from Hymenaea courbaril (XGJ) was cytotoxic to the macrophage cell line but had little effect on its proliferation. In HeLa cells, despite the absence of cytotoxicity and the increase in proliferation, XGJ (200 μg/mL) affected the cell metabolism by reducing the oxygen consumption (~47%) of permeabilized cells. XGJ also promoted an increase (~26%) in lactate levels in the supernatant of nonpermeabilized cells, while pyruvate levels were not significantly affected. The results show that PEP might be studied in regard to its immunomodulatory function and XGJ can be investigated by its effects on tumor cell metabolism.