In which country did the digestive biscuit originate?

The digestive biscuit originated in Scotland.

Digestives were developed in 1839 by two Scottish doctors, who intended the biscuit to aid digestion. The name reflects a period belief that sodium bicarbonate and other ingredients could give the biscuit antacid or digestive properties. Some early producers also used diastatic malt extract, which helped break down starch in flour before baking.

The biscuit is a semi-sweet type usually made with wholemeal or coarse brown wheat flour, sugar, fat, salt and raising agents. Its crumbly texture and mild sweetness make it popular with tea and coffee, especially in Britain. The name describes an old health claim, not a modern medical benefit.

McVitie's began manufacturing its famous digestive in 1892, using a recipe developed by Sir Alexander Grant. Chocolate-covered versions appeared later: McVitie's introduced its Chocolate Homewheat Digestive in 1925. Digestives are also widely used as the crumb base for cheesecakes and other no-bake desserts.