Cardiac glucoside, also known as cardenolides, are a type of chemical compound that affects the heart by slowing its rate and increasing the force of contractions. These compounds are commonly found in plants such as foxgloves and milkweeds and are used in medications to treat heart failure and other cardiovascular conditions. Synonyms for cardiac glucoside include digitalis, digoxin, and ouabain. These compounds have been used for centuries, with the first recorded use of digitalis dating back to the 18th century. While they can be effective in treating heart conditions, cardiac glucosides must be used with caution as they can also be toxic if not properly administered or monitored.