Nurses' and doctors' leaders have called on the UK Government to tackle the "poaching" of overseas healthcare workers, at next month's G8 summit.
Many doctors from overseas apply to work in the UK each year
They say staff migration from developing nations is killing millions and compounding poverty.
The British Medical Association and the Royal College of Nursing have written to Tony Blair demanding urgent action.
They praise the UK's stance on "ethical recruitment", but call for other G8 nations to make similar commitments.
Sub-Saharan African countries are some of the worst hit by the "brain-drain".
The World Health Organization estimates that one million more healthcare workers are needed in these countries if they are to meet basic health goals, such as reducing childhood and maternal mortality.
Last month, UK doctors warned in the Lancet that the UK was crippling sub-Saharan Africa's healthcare system by poaching its staff.
BMA chairman James Johnson said the consequences of poaching on the developing world were "absolutely catastrophic".
"There are large areas of Africa where there are no health workers of any kind," he told BBC Radio 4's Today programme.
"The countries of the developed world have helped themselves liberally to doctors and nurses from the developing world for very many years."
The joint letter, by Mr Johnson and RCN General Secretary Beverly Malone, says the G8 nations must address the exodus of healthcare workers from the developing world if they are to tackle global poverty.
It praises the government for taking a "strong moral lead" on global poverty.
But it warns that efforts to deal with HIV and other health crises in the developing world are being hampered by the staff shortages.
The UK does have an ethical code which means it will not actively recruit from certain developing countries, including those in sub-Saharan Africa.
However, healthcare professionals from these countries are free to apply for jobs in the UK.
The UK Government says it is working to create more home-grown doctors to staff the NHS, but it still relies heavily on healthcare professionals from overseas.
Currently, nearly a third of the doctors practising in the UK were actually trained overseas.
In comparison, only 5% of doctors in Germany and France are not home grown.
"The UK Government has led the way in establishing a code of good practice for ethical recruitment," the letter says.
"It is now essential that other developed countries, such as the US, make a similar commitment to address the issue."
Copies have also been sent to the ministers responsible for health in Northern Ireland, Scotland, and Wales.
Health Minister Lord Warner said: "The agenda for the G8 summit is focusing on the particular needs of Africa in seeking ways to develop healthcare systems on a sustainable basis and it will be important to consider issues around recruitment and retention of local health service staff."
Liberal Democrat Shadow Health Secretary, Steve Webb MP said: "This a global problem which needs a global solution.
"Britain should lead the G8 countries in working towards an international agreement to limit the number of nurses and doctors being recruited from vulnerable countries."