Amid a war of words over currency and the EU, the breast cancer surgeon from Troon made a speech in May that has become an internet hit.
Addressing Women for Independence, she blasted the private-sector reforms in the English NHS and claimed a No vote would mean the end of the Scottish health service within 10 years.
The First Minister is now loudly banging the NHS drum, while Labour has described the claim as the "biggest lie" of the referendum.
How does she feel to have entered the political world?
"A bit weird," she says, in a cafe in Glasgow. "All of this just came from that one speech being put on YouTube and going viral ... I'm very much a fish out of water."
A socialist with a "small s", Whitford was a natural Labour voter until the Iraq war. The 55-year-old recently joined the SNP.
On the NHS, her argument seems to be that the increasing role of the private sector down south will ultimately put pressure on the Scottish health budget.
However, Holyrood gets its budget through the Barnett Formula -meaning the Parliament gets a fixed share of any public spending given to English departments. The private-sector reforms south of the Border are funded by the Department of Health in Whitehall, thus Barnett is untouched.
Does she accept that the current English policies will not affect Scottish health spending?
"Not right at the moment it doesn't, but I believe it will in the future," she replies. "In none of my speeches do I say we vote No and the next day our budget goes down. It's the long term."
So there is no immediate threat? "There isn't an immediate threat. It's trying to look ahead. That's where I see the threats."
Whitford's view is that the "direction of travel" in England will lead to full-blown privatisation, like a US-style insurance model.
Such a scheme would take an axe to the Scottish health budget, but I can think of no mainstream political party or credible politician advocating this approach.
"What you are getting is think tanks starting to talk about charges," she says. "Reform is suggesting that you would pay a monthly fee with your council tax. King's Fund is suggesting a charge of £10 to £25 to go to a GP ... It's been in The Sun, it's been in other papers, it's on chat shows and talk shows."
I suggest think tanks invariably produce loopy proposals that are ignored.
"But there's huge amounts of discussion of it," she says.
"People phoning in and saying 'I would pay £10 to save the NHS, I would happily pay £25 to save the NHS'. But if you are actually paying £25 to go to your GP, you haven't saved the NHS. That is the end of the NHS."
To accept Whitford's argument to hold, you have to make the leap that the current policy of funding private health companies will spiral into an American pay-as-you-go system.
"I don't think it's that big of a leap," she says. "The NHS in England will be a cluster of private companies, with the NHS shrivelling down to mopping up people with multiple morbidity [and] running A&Es."
However, the SNP Government has also given taxpayers' money to private health companies: around £100 million since 2011. "I don't agree with that [policy]," she says. "If we get a Yes, I'm not going to be easy-peasy on these guys either." She is also worried about the "scary" effect of the Transatlantic Trade and Investment Partnership (TTIP) on the NHS.
The TTIP is intended to remove trade barriers between the US and the EU, but critics fear it could open up public services to American multinationals.
I put it to her that, given the US is our largest individual trading partner outside the UK, the agreement could be seen as especially good news for Scotland.
"I don't think so," she says, adding that TTIP is an "incredibly poor deal". However, I read her a quote on TTIP from last year: "For Scotland, given that the USA is our largest individual trading partner outside the UK - our trade with the EU as a bloc is greater - the agreement will be especially good news."
This was said by First Minister Alex Salmond.
"I think probably he hadn't looked enough at the small print," she laughs. "Don't you go and get me into trouble!"
What does she make of Labour's "biggest lie" claim?
"I'm not lying," she says. "I'm not looking to gain anything. I obviously was not particularly expecting this big explosion of the issue, but it was an issue that I thought was important."
Regardless of your position on Whitford's NHS claims, it would be difficult not to admire her on a professional level.
She refuses to carry out private-sector work - "I just don't believe in it" - and would be happy to see the end of the lavish distinction awards some of her colleagues enjoy.
However, don't expect her to swap medicine for elected politics if there is a Yes vote.
"I don't think I could stand it," she says. "Sitting in the back of the chamber, listening to speeches all day, I don't see it."
And what if Scotland votes No?
"I'll put my head under the duvet and cry for a few days," she says. "But I'll quickly realise I've got work to do."