Cholesterol is a naturally-occurring steroid found in animal tissues. It's important for healthy cell membranes and other functions, but its waxy makeup makes it a danger as a high concentration could build up and block arteries.
Cholesterol is a product of the liver, excreted through bile into the digestive tract. The first notice of cholesterol was in 1769, when a French researcher found it in gallstones. Then, in the early 19th Century the chemical was named "cholestrine," from the Greek words for bile (chole) and solids (stereos), plus the chemical suffix -ol. Scientists have noted the role of cholesterol in heart attacks and other health problems, a situation that can be regulated through diet or medications.