To determine whether honey and sucrose would have differential effects on levels of neutrophil phagocytosis after long-term feeding 36 2-month old Sprague Dawley rats were fed a powdered diet that was either sugar-free or contained 7.9% sucrose or 10% honey (honey is 21% water) ad libitum for 52 weeks. The percent of neutrophils exhibiting phagocytosis, and the percentage of leukocytes that were lymphocytes were then measured by flow cytometry after 52 weeks. Results: Neutrophil phagocytosis was similar between sucrose- and honey-fed rats, and lower in rats fed the sugar-free diet (79.2%, 74.7% and 51.7 %, respectively). The percentage of leukocytes that were lymphocytes differed significantly between all three treatments, the levels being highest in honey-fed rats (53% vs 40.1% and 29.5% for sucrose- and sugar-free fed rats). In conclusion: Honey may have a beneficial effect on immune activity, possibly attenuating the decline seen in older age.