Commonly seen on doctor’s prescription pads and signs in pharmacies, Rx is the symbol for a medical prescription. According to most sources, Rx is derived from the Latin word “recipe,” meaning “take.” Among several alternative theories, however, is the belief that the Rx symbol evolved from the Eye of Horus, an ancient Egyptian symbol associated with healing powers.

What is known for certain is that the practice of pharmacy, the preparation and dispensation of drugs, has been around for thousands of years. The world’s first recorded prescriptions were etched on a clay tablet in Mesopotamia around 2100 B.C., while the first drugstores were established in the ancient city of Baghdad in the eighth century A.D.

America’s earliest drugstores date to the 17th century, in places such as Boston and New York. Before he became infamous as a traitor during the Revolutionary War, Benedict Arnold was an apothecary, or pharmacist, in Connecticut. The first college of pharmacy in the United States was founded in 1821 in Philadelphia. In the late 19th century, it was an Atlanta pharmacist, John Pemberton, who invented the formula for what would become Coca-Cola. At the time, Pemberton claimed his new concoction cured a variety of afflictions.

Prior to the 1950s, the majority of prescription medications in America were compounded by pharmacists; that is, each medication was custom-made from raw ingredients to suit an individual patient’s needs. After the mid-20th century, pharmacists filled most prescriptions with mass-produced products from drug companies. Today, the mortar and pestle, used by pharmacists for centuries to make medications, remains an industry symbol, often appearing on drugstore signs along with Rx.