The purpose of these experiments was to determine whether quantitative changes take place in the attached sugars of hepatic (postmitochondrial) glycoproteins isolated from rats fed a diet supplemented with citrus bioflavonoids (an equal mixture of rutin, naringin, and hesperidin) (B) and/or ascorbic acid (C) for 40 days and 90 days. Statistically significant increases in body weights (P < .05) were observed in the B-only groups and liver weights in the CB group (P < .01-.05) after 40 and 90 days of feeding the experimental diets, while liver weights were decreased in the B-only groups after 40 days of feeding (P < .05). In the acid-soluble glycoprotein fraction, statistically significant decreases were seen in bound hexoses and fucose (P < .05) in the CB group after 40 days, and in bound fucose only after 90 days (P < .05). In the acid-insoluble glycoprotein fraction, statistically significant changes were seen in bound hexoses and fucose (P < .05) in the CB group after 40 days, and in bound fucose only in the CB group after 90 days (P < .05). There is an apparent overall decrease in the sugar-rich acid-soluble glycoprotein fraction that is accentuated even further by combined CB supplementation. This decrease is more probable after 40 days than it is after 90 days of dietary supplementation. An adaptive phenomenon is suggested for maintaining the intracellular environment during periods of dietary citrus bioflavonoid and/or ascorbic acid supplementation.