This study isolated phenolic-rich extracts from strawberry (ES) and mulberry (EM) fruit juice using 70% ethanol, analyzed the individual phenolics including four flavonoid components using HPLC and assessed their cytokine secretion regulatory activities using murine primary splenocytes and peritoneal macrophages. The results showed that EM was rich in p-coumaric acid (20798±719μg/g dry weight), rutin (1992±26μg/g dry weight) and quercetin (81±5μg/g dry weight), but ES was relatively rich in p-coumaric acid (7475±1219μg/g dry weight), morin (101±68μg/g dry weight) and quercetin (72±42μg/g dry weight). ES and EM administration significantly decreased splenocytes' (IFN-γ+IL-2+IL-12)/IL-10 (Th1/Th2) cytokine secretion ratios in the absence or presence of lipopolysaccharide (LPS) and TNF-α/IL-10 (pro-/anti-inflammatory) cytokine secretion ratios in the presence of LPS in dose-dependent manners. Our results suggest that ES and EM that are rich in p-coumaric acid, rutin, morin or quercetin, may have strong immunomodulatory effects on splenocytes, via decreasing Th1/Th2 and pro-/anti-inflammatory cytokine secretion ratios.