Some features of pills that help people identify them are their imprints, colors, sizes, shapes and types of scoring, according to the National Library of Medicine. The FDA requires drug manufacturers to include a unique imprint on each solid, orally delivered medication in the United States, says Drugs.com.
Pill imprints can include single letters, single numbers, symbols, and combinations of letters and numbers, explains Drugs.com. They can also include whole words, company names and National Drug Codes. Another identifying factor is a pill's type of scoring. A pill score is a line down the middle of the pill that allows for easier splitting.
People can use features such as imprints, shapes, sizes and colors to identify unknown pills by entering them into a free online pill-identification tool, such as Drug.com's Pill Identifier or the National Library of Medicine's Pillbox. For example, a search for the imprint "213," the shape "oval," and the color "blue" in Pillbox yields a result of "sertraline hydrochloride 50 milligram oral tablet." Entering more than one feature yields more specific results.
Although each pill's imprint code is unique, imprint codes on different pills can have strings of several letters or numbers in common. For example, a search in Drug.com's Pill Identifier for the imprint "213," without entering the color, shape or any other features, produces several pages of results.