Cassava roots and tubers from which gari is made, has been confirmed to contain what some amount of cyanide which helps defend them against herbivorous animals. Although the cyanide produced in cassava plant is poisonous, and can be harmful to humans, properly processing the gari would reduce the concentration of this acid to a harmless level.
However, impatience on the part of some gari producers may lead to the production of gari with some amount of harmful cyanide which may be harmful to the eyes. Luckily, the process of fermentation and frying has led to the production of gari that are safe for consumption.