A digestive biscuit, sometimes described as a sweet-meal biscuit, is a semi-sweet biscuit that originated in Scotland. The digestive was first developed in 1839 by two doctors to aid digestion. The term digestive is derived from the belief, around the time the biscuit was first introduced, that they had antacid properties due to the use of sodium bicarbonate as an ingredient. Historically, some producers used diastatic malt extract to "digest" some of the starch that existed in flour prior to baking.