The results showed that LY294002 pretreatment notably decreased the phosphorylation level of Akt compared with the osthole group in gastric cancer cells, and restored osthole induced down-regulation of cyclin B1 and cdc2 in human gastric cancer cells, implying that osthole may suppress gastric cancer cell cycle arrest via down-regulating PI3K/Akt signaling. The gene discussed is CCNB1; the disease is gastric cancer.