A campaign against loan sharks is being stepped up by the Office of Fair Trading and trading standards officers.
About 200,000 leaflets and posters will be handed out to warn people of the danger of borrowing money from illegal, and sometimes violent, lenders.
The campaign is particularly aimed at households in Scotland, the North of England and the West Midlands.
It is thought these areas contain about half the 165,000 homes in Britain who borrow cash from loan sharks.
"Unlicensed loan sharks will often offer cash loans without paperwork, they may take benefit or bank cards as security, and threaten or use violence to get money," said the OFT.
The regulator said its work had already assisted 11,500 people and led to £31m of illegal loans being written off, with prison sentences being handed out to some unlicensed money lenders.
The campaign will highlight the dangers of being charged exorbitant interest rates as well as the possibility of suffering threats and violence.