Four in ten European doctors are considering leaving Britain following the Brexit vote, according to research.
The figure comes from a British Medical Association (BMA) survey which found that 42% are thinking of quitting the UK, with a further quarter (23%) still unsure.
The BMA in Scotland warned that the ongoing uncertainty faced by European doctors is "deeply damaging".
Around 10,000 doctors who work in the NHS - 6.6% of the UK medical workforce - qualified in Europe.
The doctors' union polled 1193 doctors from the European Economic Area (EEA) who are working in the UK.
It found that they feel "significantly less committed" to working in the UK following the EU referendum. They also feel "substantially less appreciated" by the UK Government in the wake of the result.
BMA Scotland chairman Dr Peter Bennie said: "This survey should set alarm bells ringing in Government.
"It shows just how much damage is being done by the needless and continuing uncertainty over the future status of European doctors who already work in our NHS.
"These are our colleagues and our friends and the ongoing uncertainty they face is deeply damaging.
"Many European doctors have dedicated years of service to healthcare in the UK, so it's extremely concerning that so many are considering leaving."
He went on: "The refusal of the Westminster Government to guarantee their right to continue contributing to our health service is understandably causing a significant number of European doctors to consider leaving the UK, regardless of what future agreement is reached.
"We should be in no doubt that the scale of the recruitment and retention difficulties that Scotland's NHS is facing would be made exponentially worse without the contribution of European doctors."
BMA Scotland has welcomed the Scottish Government's position of wanting to protect the future rights of European NHS staff.
Health secretary Shona Robison said the findings are "deeply concerning".
"The free movement of workers across Europe has made a huge contribution to NHS Scotland's reputation for world-leading care," she said.
"Doctors, nurses and care workers from across Europe help to staff our GP surgeries, our hospitals and our care homes.
"We must as a priority protect their right to live and work in this country, as well as our ability to attract their counterparts in years to come - and the Scottish Government is pursuing all options to protect our place in the single market."
A Department of Health spokeswoman said: "Overseas workers form a crucial part of our NHS and we value their contribution immensely."