According to the U.S. Food and Drug Administration, the bitter-tasting berries of the Pyracantha bush, popularly known as Firethorn, are not known to be poisonous in small amounts. Action should be taken only if the berries have recently been sprayed with insecticide.
In 1957, the Arizona Poisoning Control Information Center received numerous calls about the toxicity of Pyracantha berries. The center conducted tests on various animals in which the animals were given large amounts of the berries over a period of 10 days. None of the animals exhibited any ill effects from consuming the berries.
Pyracantha berries are commonly used to make jelly and jam. Pyracantha jelly is similar in taste to apple jelly. Since the berries are very bitter, a large amount of sugar is used when making the jelly or jam.