Ms MacDonald is attempting to make Scotland the first part of the UK that would give seriously ill patients the right to end their own lives.
The special Scottish Parliament committee set up to hear evidence on the bill yesterday heard from those who disagree with her proposal on moral grounds.
In a submission presented to the committee, Elaine Stevens of the Independent Association of Nurses in Palliative Care, suggested that a law change would result in people flocking to Scotland in order to end their lives.
She made her point, even though the bill proposes that anyone requesting assistance to die must be registered with the medical practice involved at least 18 months beforehand.
But in her submission she said there were "many ways around the system", including patients registering with a practice outwith the area they live in and not using the service.
She asked: "Does Scotland really want to be recognised as a 'death tourism' destination?"
Ms MacDonald wants to change the law, which leaves Scots open to prosecution for culpable homicide if they help someone commit suicide.
The committee scrutinising the End of Life Assistance Bill has also heard from those running hospices, which provide palliative care for the terminally ill.
The submission of Maria McGill, the chief executive of the Highland Hospice, outlined strong opposition.
"We stand resolutely against assisted dying which, contrary to the assertions of the bill, is at variance with the principles and practice of palliative care," she said, adding that the right to die would create "ethical and legal dilemmas" for healthcare professionals when they are under increasing pressure to ensure safe practice.
Dr Chris Sugden, medical director of the St Andrews Hospice in Lanarkshire, added: "The bill appears to have been created for the few at the expense of the many: the many frail, vulnerable patients that we care for across a broad spectrum of age who are in danger of viewing the medical profession with fear and suspicion."
The committee heard that the bill could "inhibit" dialogue with terminally-ill patients and lead to fears that they could be seen as directing people towards assisted suicide.
Labour MSP Helen Eadie warned: "We could see the development of specialist GPs or specialists who actually provide this particular service."
Mark Hazelwood, of the Scottish Partnership for Palliative Care, said if private GPs were getting significant income from this kind of work, it could become difficult to ensure no "conflict of interest".