The introduction of smaller-sized packets of paracetamol has led to a 43% reduction in the number of poisoning deaths, a study suggests.
The number of liver transplants due to paracetamol overdoses has also significantly reduced thanks to the legislation to make pack sizes smaller, researchers said.
In 1998 packs were restricted to a maximum of 32 tablets through pharmacy sales and 16 for non-pharmacy sales to stem the large number of people taking paracetamol overdoses.
Researchers wanted to investigate the long-term impact of the legislation in England and Wales.
They examined data concerning poisoning deaths between 1993 and 2009 and liver unit registrations between 1995 and 2009.
Their findings, published on bmj.com, suggest a "significant decrease" in deaths involving paracetamol.
There was an average of 17 fewer deaths for every three months compared to before the legislation was introduced. This resulted in an overall decrease of 43% in the 11 year post-legislation period.
There was also a 61% reduction in the number of paracetamol-induced liver transplants in England and Wales following the legislation.
But in spite of the law there are still 121 paracetamol poisoning deaths each year, the researchers added.