Selling painkillers in smaller sized packs has slashed the number of suicides caused by overdoses in Britain by almost 25 percent, a study released on Friday said.

Government legislation in 1998 cut the size of packs of paracetamol (acetaminophen) and aspirin and limited the number of tablets retailers were allowed to sell.

Researchers from Oxford University, who looked at suicide rates and non-fatal overdoses across the UK from 1993 to 2003, found that in the three years after the law was brought in, overdosing from paracetamol and salicylates (aspirin) significantly decreased.

However the number of overdoses from ibuprofen, which was not covered by the new legislation, remained unchanged.

The number of liver transplants necessitated by paracetamol poisoning also dropped by 30 percent in the four years after the legislation came into force, according to the research published in the British Medical Journal.

“We are particularly pleased that one of the government’s initiatives to reduce the suicide rate has apparently been successful,” said Marjorie Wallace, chief executive of mental health charity SANE.

“However, we must not forget that overdosing is only one of the ways in which people sadly take their own lives: the most common method of suicide for young men is hanging.”

The researchers said although the laws did not stop someone buying multiple packs from more than one retailer, many of those who took overdoses did so impulsively using the tablets they had at home.

They called for packs to be made even smaller saying it would further help to reduce the number of deaths.