UK objections at Maastricht had meant that the social chapter had never passed into law.
But at Amsterdam, the newly-elected UK government dropped its opt-out making the social chapter part of the Treaty.
The sections of the Maastricht treaty on public health and consumer protection were toughened up, in reaction to public concerns over mad cow disease and other health scares.
Amsterdam aimed to make the EU more democratic in preparation for its eastwards enlargement.
The European Parliament was given powers to legislate in co-decision with the Council of Ministers on a range of new issues including employment, social policy, health, transport and the environment.
In the Council of Ministers, unanimity was replaced with qualified majority voting on employment, social exclusion, customs and data protection amongst other issues.
The Amsterdam Treaty also provided for a two-speed Europe by allowing closer co-operation between countries wanting to forge ahead on certain issues.
Another important aspect of Amsterdam is the abolition of border checks by incorporation of the Schengen agreements into EU law for all member states except Britain and Ireland.
The union members also agreed to co-ordinate their approach to asylum and immigration as well as increasing co-operation on police and law enforcement.