Known as ege (Yoruba), akpu (Igbo), rogo (Hausa), it is a cheap source of carbohydrates, but low in other nutrients and as such it tends to be eaten with protein and vitamin-rich foods. Many varieties (so-called ‘bitter cassava’) contain cyanide and must therefore be properly prepared before consumption. The most popular form of processing in Nigeria is fermentation which produces garri, a fine grain similar to polenta. Other varieties (‘sweet’) are prepared by peeling and boiling.