NHS staff are regularly using food banks and taking out high-rate loans just to make ends meet, new research claims.
Unison's annual survey of 21,000 workers revealed one in 10 had pawned possessions, while a similar number had taken out a payday loan.
Almost one in seven said they had remortgaged their home or even moved to a cheaper property as they could no longer afford to live there.
Nearly one in five had taken on an extra job - and four out of five said they had considered resigning.
The union estimated £4.3 billion had been cut from NHS salaries over the past six years because of pay freezes in the public sector.
And it warned some pay grades could soon fall below national minimum wage levels.
Unison's head of health Christina McAnea said: "These figures paint a shocking picture of the effects of pay restraint on hard-working NHS staff.
"They're having to sell or pawn their belongings, move house or ask relatives for financial help while doing critical and life-saving jobs in our health service.
"The NHS already has significant staff shortages in key services, but our survey shows more than half of NHS workers are seriously considering leaving their jobs as a result of dwindling pay and increased workloads - this is a message the Government cannot ignore.
"NHS staff are now 14% worse off than they were in 2010, NHS finances are tighter than ever, pressure and demand in the system continues to grow, inflation is expected to rise and something has to give.
"The Government needs to act now, starting with a clear strategy for improving pay before the situation deteriorates even further and we are faced with an exodus of hard-working, caring staff."
Health unions have made a submission to the NHS Pay Review Body for a pay rise which reflects the increase in the cost of living.
A Department of Health spokesman said: "The dedication and sheer hard work of our NHS staff is absolutely crucial to delivering world-class care for patients.
"The Government has had to take difficult decisions over the public finances, but we will continue to fund public sector pay awards, including for NHS staff, at an average of 1% next year."