Particular Cornus species are known for their edible fruits and their leaves are used as a tea in some countries. In the present study, the immunomodulatory activity of water infusions of leaves of Cornus mas (CM), C. kousa (CK), C. alba (CA), C. flaviramea (CF), C. coreana (CC) and C. amomum (CU) was tested on human leukocytes. Phagocytic and antimicrobial activity was determined for concentrations of 0.17 and 0.25 mg x mL(-1). All samples significantly enhanced the phagocytic activity of cells. Samples at the concentration of 0.17 mg x mL(-1) were in all cases, except CK, slightly more effective than those at 0.25 mg x mL(-1). The strongest bactericidal (E. coli) and also candidacidal (C. albicans) activity was exerted by CM at 0.25 mg x mL(-1). The most potent samples at the lower concentration were CF (for E. coli) and CK (for C. albicans). CC and CU were antimicrobially non-effective.