In order to test for an effect of phosphate buffered saline (PBS) treated externally with Qi energy ("Qi-treated" PBS) on the phagocytic activity of human polymorphonuclear leukocytes (PMNs), rigorously controlled experiments employing masking and randomized procedures were carried out under independent monitoring. In all experiments, Qi treatment was externally applied under monitoring to newly purchased unopened 100 ml bottles of PBS, and the PMN phagocytic activity was assayed by one experimenter in masked, randomized and monitored conditions using a highly sensitive chemiluminescence method. Phagocytic activity data were obtained in triplicate for each sample and then statistically analyzed. The PBS samples Qi-treated by the Qi-gong master and by one of the Qi-gong trainees showed clear stimulation of PMN phagocytic activity which was significant statistically, and this phenomenon was highly reproducible. Out of 10 experiments by the Qi-gong master, only twice did Qi-treatment fail to influence the PBS. The activity of Qi-treated PBS decayed over days or weeks. Furthermore, it was found that Qi-treated PBS had decreased phagocytic stimulatory activity after microwave treatment, but not after autoclave treatment. We also demonstrated that microwave irradiation and infrared laser pulse irradiation have similar effects on PBS as Qi-treatment. The results obtained in this experiment provide evidence of the existence of Qi energy, its ability to influence an electrolyte solution and its biological effect. Furthermore, microwave or infrared laser pulse treatment was found to partly mimic the Qi-treatment of PBS.