For flaxseed oil exhibited ameliorating polycystic ovary syndrome effect on letrozole-induced rats (61), Firmicutes/Bacteroidetes ratio was positively correlated with E2, PROG, T, IL-1β, TNF-α, and MCP-1 in plasma and with IL-6, IL-17A, and MCP-1 in the ovary and was negatively correlated with IL-10 in the ovary. The gene discussed is CCL2; the disease is polycystic ovary syndrome.