This document defines autacoids as organic substances produced in one part of the body and transported to another part where they exert physiological effects. It discusses the main types of autacoids - amines, lipids, peptides - and provides details on histamine and serotonin, including their synthesis, receptors, pharmacology, therapeutic uses, and adverse effects. Prostaglandins and leukotrienes are also covered, outlining their actions, uses, and risks.