Every change in chemicals involves energy. Energy is, therefore, an essential and integral part of all chemical studies. Energy, inter convertible with chemicals, can even be taken as a property of the later. Matter is only a trivial name for chemicals. The health effects depend on the nature, and route of entry of a chemical, and on the genetic make up, body weight, and sex of the individual exposed, but primarily on the dose.
All chemicals are harmless or beneficial in small amounts.
Defined by LD50, a spoonful of botulinium toxin can be lethal to the entire population of the United States. But traces of this deadly toxin is the active ingredient in Botox injections that fight muscle spasm disorders. All chemicals are harmful in too large a quantity. A tablespoon of salt is lethal to an infant, an adult can commit suicide with 100 aspirin tablets, and a Florida girl died a few years back from drinking too much water over years. It is the dose that makes the poison.