The Green Party has pledged to put an end to the "pain of privatisation" in the NHS.
Party co-leader Caroline Lucas is set to outline plans to remove the market from the health service, saying the last Tory government's management of the NHS was akin to "a cruel form of shock therapy".
While focusing her attack on the Conservatives, Ms Lucas is also set to condemn Labour and the Liberal Democrats as she launches the policy in the Isle of Wight.
She will say: "A confident and caring country is one where we provide people with the healthcare they need, free at the point of use.
"That's why my party is today promising an end to the pain of privatisation that has been inflicted on the NHS by Labour, the Lib Dems and the Conservatives - we will give the NHS the funding it needs to meet the challenges of the 21st century.
"The current government is putting our NHS through a cruel form of shock therapy, leaving patients at risk and hospitals under extreme pressure.
"The Green Party will reverse this race to the bottom on health provision and reinstate our health service to make it a world leader.
"Indeed, if you look at the record of all of the other major parties, it's clear that only the Green Party can be trusted on protecting the NHS."
The Green Party's NHS spending plans will be paid for through higher taxation outlined in its manifesto, which is expected to include higher corporation tax for big businesses, increased income tax for the better off and changes to inheritance tax.