The milligram is a unit of mass in the International System of Units (SI) that measures the weight of extremely small quantities of substances. It is equivalent to one-thousandth of a gram or one-millionth of a kilogram. The symbol for milligram is 'mg'. Widely used in medicine, chemistry, and nutrition, the milligram is crucial for accurately measuring and expressing the mass of small amounts of medications, chemical compounds, and nutrients. For instance, medications are often prescribed in milligram dosages to ensure therapeutic efficacy and safety. In scientific research and everyday applications, the milligram provides a precise and standardized unit for quantifying minute amounts, making it indispensable in various practical and scientific contexts.