Metal ions are poorly known whereas they sometimes play a role more significant than vitamins. Moreover they control many diseases, such as the zinc salts in dermatology. Another example is the recent discovery of platinum co-ordination compounds' anti-tumour activity (cisplatine). There is a growing volume of literature too. The chemistry of metal ions has provided new insights into DNA, proteins and membrane chemistry, as well as the physiopathology of diseases. 2nd International Symposium on Metal Ions in Biology and Medicine, Athens, May 1992.