Saponinum album, a mixture of triterpenoic saponins derived from Gypsophila species, led to an increased internalization of agrostin, a ribosome-inactivating-protein (RIP) type I in U-937 cells differentiated with interferon-gamma or phorbol myristate acetate. Treatment with agrostin only showed no cytotoxicity. It was hypothesized that saponinum album stimulated phagocytosis and by that the uptake of agrostin. For this purpose phagocytosis experiments with Alexa-Fluor-488-labelled 1-microm amino-latex beads and FITC-labelled Escherichia coli (K-12 strain) were performed. The results indicated no stimulation of phagocytosis by treatment with saponinum album.