blood sausage is any sausage made by cooking animal blood with a filler until it is thick enough to congeal when cooled. pig or cattle blood is most often used. typical fillers include meat, fat, suet, bread, rice, barley and oatmeal. varieties include biroldo, black pudding, blood tongue, blutwurst, drisheen, kishka (kaszanka), morcilla, moronga, mustamakkara, sundae, verivorst, and many types of boudin.