To test whether mistletoe can have an inducing phagocytic activity, kidney leucocytes from tilapia fed with mistletoe (0, 10, 50 and 200 mg) were incubated overnight with zymosans. As shown in Fig. 4, the significant increased phagocytic activity appeared in groups C and D on day 40, 80, and the post-challenge period compared to the mistletoe non-fed control group. No significantly different (p>0.05) phagocytic activity between groups C and D was observed at all assayed periods. Significantly higher relative survival percentage compared to the control. Group C showed the highest survival rate of 80.00% (Fig. 5).