The human body contains about 50 of the elements in the Periodic Table, about half of these are either essential or beneficial to life, while the remainder are adventitious having been introduced from local dietary or environmental influences. Ten of these essential elements, oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, sulphur, potassium, sodium and chlorine, are present in amounts ranging from tens of kilogrammes to a few tens of grammes, and these so called bulk elements are contained in the proteins, fats and carbohydrates that are the building blocks for the organs and tissues. The major emphasis of this review will rest on the remaining twenty or so of the essential and beneficial elements which, because they are generally present in very small quantities, are often called trace elements. The total mass of these elements in the human body is less than 50 grammes, yet they must be present in the correct concentrations and forms if the individual is to enjoy a healthy life.