[The Helsinki Declaration: relativism and vulnerability].

The Helsinki Declaration is a crucial ethical landmark for clinical research involving human beings. Since the Declaration was issued, a series of revisions and modifications have been introduced into the original text, but they have not altered its humanist approach or its international force for regulating clinical research. A proposal for an extensive revision of the Declaration's underlying ethical principles has been debated for the past four years. If the proposal is approved, international clinical research involving human beings will be modified, further increasing the vulnerability of certain social groups. This article discusses the historical process involved in passing the Helsinki Declaration and the most recent debate on the new draft. The article analyzes the new text's social implications for underdeveloped countries, arguing for a political approach to the vulnerability concept.