Latex is a milky white liquid that comes from certain plants, especially rubber trees. When you break a dandelion stem and see white sap ooze out, that's latex. Rubber trees produce latex that can be collected and processed into rubber for tires, erasers, rubber bands, and countless other products.

The discovery that latex from rubber trees could be turned into useful rubber transformed industries around the world. In the 1800s, inventors learned how to make this natural material more durable and stretchy, leading to rubber boots, waterproof clothing, and eventually automobile tires. Today, workers tap rubber trees by carefully cutting into the bark and collecting the latex that drips out, much like collecting maple sap for syrup.

The word latex also refers to synthetic materials designed to mimic natural rubber latex. Latex paint, for instance, uses synthetic latex that makes the paint flexible and easy to clean up with water. Latex gloves, commonly used by doctors and dentists, can be made from either natural or synthetic latex.

Some people are allergic to natural latex, which is why hospitals now often use non-latex gloves and why balloon packages sometimes specify whether they contain latex.