The prostaglandins are lipids produced during tissue damage or infection that regulate processes like inflammation, blood flow, blood clotting, and childbirth. They act as vasodilators to lower blood pressure, cause inflammation at sites of injury to initiate healing, regulate contraction of gastrointestinal and respiratory muscles, and influence immune function, renal function, metabolism, and female reproduction such as ovulation and inducing labor. High or low levels of prostaglandins can impact health, so herbs, drugs, and hormones are used to regulate their levels.