What astonished me was the very low toxicity of a substance that has such very great physiological power. A little pinch, 5 mg, every day, is enough to keep a person from dying of pellagra, but it is so lacking in toxicity that ten thousand times as much can be taken without harm.

Statement about vitamin B3, (either niacin or niacinamide), in How to Live Longer and Feel Better (1986), Avon Books, ISBN 0-380-70289-4, p. 24