U.S. Senator Bernie Sanders/Facebook Canadian doctor Danielle Martin spoke with U.S. Sen. Bernie Sanders on his radio show Thursday.

The single biggest issue with the Canadian health care system is its lack of a national pharmacare program, a Toronto doctor told U.S. Sen. Bernie Sanders on Thursday. Dr. Danielle Martin made the comments on Sanders' radio show, one day after she appeared alongside the senator as he introduced a new bill proposing a four-year transition period to change American Medicare into a single-payer system.

Bill Clark via Getty Images Dr. Danielle Martin (left) watches as Sen. Bernie Sanders speaks during his event to introduce the Medicare for All Act of 2017 on Sept. 13, 2017.

The physician, who works at Women's College Hospital in Toronto, called it a "big problem" that Canadians have to pay for prescription drugs used outside of hospitals. She called the system outdated. "And it's because our system was designed in the 1960s when prescription medication was less of a focus of medical care," Martin said. "Today, it's a cornerstone in the management of chronic disease and I don't think you can have a well developed universal health care system that doesn't include prescription medicines." A national pharmacare program the "next frontier" for the Canadian medical system, she said. They call it, actually, the third rail of Canadian politics — If you touch medicare, you get fried.Dr. Danielle Martin Canada is unique in that medicare is more intrinsic to the Canadian identity than it is to the American identity. Martin said it's rarely used as a wedge issue, adding few politicians risk making overtures to dismantle it. "They call it, actually, the third rail of Canadian politics — if you touch medicare, you get fried," she said. "There's been a leadership race for the Conservative Party, and there was one candidate in the race for the leadership of the Conservative Party who suggested we should allow two tier health care and she was trounced."

Bloomberg via Getty Images Kellie Leitch speaks during the final Conservative Party of Canada leadership debate in Toronto on April 26, 2017.

That reference was to Kellie Leitch, who in January suggested to Fox News' Business Network that she doesn't agree with universal health care. Leitch, a former orthopaedic surgeon, finished sixth in the leadership race. Sanders, who has been advocating for universal health care since the 1990s, is calling the latest version of his health care vision "Medicare for all." At one point during Sanders' rally, Martin took out her Ontario health card to make a point about the simplicity of the Canadian system in comparison to the American one. "I just handed over this card, my Canadian health-care card to my doctor, and that was it," Martin said about giving birth. "I wish that all of my American neighbours could experience the same simplicity in their moments of need." Famous exchange with Republican senator A 2015 study published in the Canadian Medical Association Journal, co-authored by Martin, suggests a universal public drug coverage program could save taxpayers approximately $7.3 billion annually. Martin became a sensation in 2014 after a clip of her response to a Republican senator before an U.S. Senate subcommittee exploring health care systems around the world went viral. In the now-famous exchange, North Carolina Sen. Richard Burr's attempt to buoy private health care went awry after he asked Martin, "On average how many Canadian patients on a waiting list die each year? Do you know?" Martin responded by saying, "I don't, sir, but I know that there are 45,000 in America who die waiting because they don't have insurance at all."