Out of 10 mL of blood collected from each individual, equal volume of 4 mL was used for chromosome aberration (CA) studies and cytokinesis-blocked micronuclei (CBMN) assay while the remaining blood was used for γH2AX assay. For each CA and CBMN assays, 4 mL of blood was reconstituted with 36 mL of RPMI-1640 culture medium supplemented with 7.5% NaHCO3, 20% fetal calf serum, 200 mM L-glutamine, penicillin (100 units/mL), and streptomycin (100 μg/mL) and equally aliquoted into eight sterile vials. Two sets of vials (each set consisting of three vials) were added with the decoction at concentrations of 100, 300, and 600 μg/mL. Each set of vials served as decoction control and the test, respectively. All vials were then incubated at 37°C in 5% CO2 for 3 hrs. At the end of the 3rd hour, bleomycin at a concentration of 40 μg/mL was added to (a) a one set of vials containing three different doses of the decoction and (b) a vial without the decoction (bleomycin control) and all were further incubated for 2 hrs. A vial with addition of neither decoction nor bleomycin served as negative control. After 5 hrs of incubation, cells in each vial were washed with Hanks Balanced Salt Solution (HBSS) three times. Each sample was then reconstituted in 4.5 mL of culture medium (RPMI-1640) and used for CA and CBMN analysis as described below.