Does Vitamin C Help With Terminal Cancer?

Studies in the 1970s showed an extraordinary survival gain in terminal cancer patients with vitamin C, a “simple and relatively nontoxic therapy.” It’s no wonder it got a lot of attention, especially when reported by a world-renowned scientist, Linus Pauling. But studies in the 1980s found no such benefit, so scientists were “left with the inevitable conclusion that the apparent positive results [in the original study] were the product of case-selection bias rather than treatment effectiveness.” In the 1990s, though, an alternative explanation arose: The disappointing ’80s research only used oral vitamin C, whereas the apparently successful ’70s experiments also gave vitamin C intravenously, and we didn’t realize until the ’90s that the same dose given intravenously can lead to dramatically higher levels in the bloodstream than when taken orally. So maybe high dose vitamin C does help in terminal cancer, but maybe only when given intravenously. This is the topic of discussion in my video The Role of Vitamin C in the Treatment of Terminal Cancer.

Encouraging case reports continued to be published. Regression, remission, and cure had been documented in individual cases of advanced kidney cancer, bladder cancer, and lymphoma, but that was three success stories out of how many? If it was three out of a hundred, or even three out of a thousand, then okay, if the treatment is sufficiently nontoxic. But there is evidence that IV vitamin C is widely used in the alternative medicine world, as in 86 percent of 172 practitioners surveyed. Just those 172 practitioners alone treated about 10,000 patients a year, and manufacturers are selling hundreds of thousands of vials of this stuff in the United States. It’s not all being used for cancer, but, presumably, at least thousands of cancer patients are being treated every year with IV vitamin C, making the publication of three remarkable case reports seem less impressive. So no matter how amazing these cases seemed, it’s possible the cancers just spontaneously regressed all on their own, and it was just a coincidence that it happened after the patients were given vitamin C. To know for sure, you have to put it to the test.

To date, there have been some small pilot studies, and the results so far have been disappointing. The good news is that even insane doses of IV vitamin C seem remarkably safe, but failed in a study of two dozen patients “to demonstrate anticancer activity.” Similar small studies have been published, all the way through to the present, with results that are tantalizing but inconclusive. What we do know is that the present state of cancer chemotherapy is “unsatisfactory.” People have a perception that chemotherapy “will significantly enhance their chances of cure,” but if you put all our cancer-killing chemo together, the overall contribution to five-year survival is on the order of 2 percent—all those side effects for a 2.1 percent survival rate bump, at a cost of maybe $100,000 per patient per year. So, it may be worth looking deeper into therapies like IV vitamin C. However, the lack of financial reward (since vitamin C can’t be patented and sold for $100,000) and bias against alternative medicine “could dissuade conventional investigators and funding agencies from seriously considering this approach.”

So, decades later, what can we conclude? “After trials which have included at least 1,609 patients over 33 years, we have to conclude that we still do not know whether Vitamin C has any clinically significant antitumor activity.” Although “there is currently no definitive evidence” of benefit, the Mayo Clinic’s randomized controlled trials “do not negate the potential benefit” based on what we now know about oral-versus-IV routes of administration. So, we’re kind of back at square one: Does it work or not? There are highly polarized views on both sides, but everyone’s working off the same incomplete data. What we need are carefully controlled clinical trials. The question, though, is what do we do until then?

If it was completely nontoxic, one could argue, “Well, what have you got to lose?” But it is not—it’s only relatively nontoxic. For example, there have been rare but serious cases of kidney injury reported. After all, if it’s so safe, why did our bodies evolve to so tightly control against excess absorption? It can also be expensive and time-consuming. Each infusion can cost $100 to $200 out of pocket since insurance doesn’t pay for it, which can be quite a boon for alternative medicine practitioners. About 90 percent of the millions of doses of vitamin C being dispensed are in for-profit arrangements, so there are financial pressures pushing in both directions, for and against this treatment.

Given the relative safety and expense, though, if controlled studies even find a small benefit, it would be considered worthwhile. And if they don’t, the vitamin C question can be put to rest once and for all. But “[i]n cancer treatment we currently do not have the luxury of jettisoning possibly effective and nontoxic treatments. We should revisit promising avenues, without prejudice and with open minds…”


This video is the third installment in a three-part series. For the complete saga, watch the other two videos Intravenous Vitamin C for Terminal Cancer Patients and Vitamin C Supplements for Terminal Cancer Patients.

I discuss the conundrum of what do to about funding research of non-patentable natural treatments in Plants as Intellectual Property: Patently Wrong?.

Additional videos of interest include:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Vitamin C Pills Put to the Test for Cancer

Vitamin C “is no stranger to controversy, as evidenced by the fact that over 40 years lapsed” from the time citrus fruits were shown to cure scurvy in the 1700s and the widespread implementation of eating citrus to save lives. Is it possible we’re in the midst of a similar 40-year lag with research in the mid-1970s purporting to show that terminal cancer patients treated with vitamin C lived 4 times longer and sometimes 20 times longer? I explore this in my video Vitamin C Supplements for Terminal Cancer Patients.

Researchers at the venerable Mayo Clinic decided to put vitamin C to the test, and they failed to show any benefit. The survival curves for both groups of patients were essentially identical. In fact, the one success story, a man with end-stage pancreatic cancer who had shown no response to any previous attempts at chemotherapy but started improving and was still alive five years later, was one of the patients who got the sugar pill placebos. It was official: Vitamin C didn’t work. “The apparently positive results reported…almost certainly resulted” from systematic bias in terms of which historic controls were chosen to compare with the treatment group, read the accompanying National Cancer Institute editorial.

Linus Pauling disagreed, arguing that the prior chemotherapy in nearly all the Mayo Clinic study patients may have negated the effect of the vitamin C. If the vitamin C works by boosting your immune system but your immune system is first destroyed by chemo, the thinking goes, no wonder it didn’t work. In the original vitamin C study that showed remarkable benefit, only 4 out of the 100 patients had ever received chemo. The Mayo Clinic researchers were skeptical, but “Pauling had a legendary reputation for being right about all sorts of things,” so “one might perhaps do worse than rely at least partly on Pauling’s awesome intuition.” Thus, a second, randomized, double-blind, placebo-controlled study was performed on patients with advanced cancer, but, this time, those who had no prior chemotherapy.

Again, it was a spectacular failure.

Researchers found no measurable response. The cancer in the vitamin C group progressed just as rapidly, and the patients on the placebo sugar pills lived just as long. In fact, if anything, the sugar pill group lived longer. At two years, everyone in the vitamin C group had died, but there were still a few survivors in the placebo group who lived at least past three years. The researchers concluded that “high-dose vitamin C therapy is not effective against advanced malignant disease, regardless of whether the patient has had any prior chemotherapy.”

Because the Mayo studies were taken as definitive, the medical community concluded that vitamin C was useless. However, in the Mayo Clinic studies, they gave the vitamin C orally in supplements, not intravenously. In retrospect, the route of administration may have been key.

In the original study, Pauling and his researchers started out infusing 10 grams of vitamin C a day intravenously, whereas in both of the Mayo studies designed to replicate the protocol, the researchers just gave people vitamin C supplements to take orally. Patients were sent home to swallow 20 capsules a day. They got the same dose, but 10 grams given orally is not the same thing as 10 grams given intravenously. They can’t be blamed for their ignorance, though. This fact wasn’t discovered until decades later.

It turns out vitamin C concentration in our bloodstream is tightly controlled, such that if you try to swallow more than you’d get eating five servings of fruits and vegetables, your body cuts down on the absorption in the intestine. For example, if you go from eating 200 mg to eating about ten times more (2,500 mg), the level in your bloodstream only goes up 3 mg per liter or quart of blood. “In contrast, because intravenous injection bypasses the intestinal absorption system,” it can result in super high blood concentrations—as in 100 to 200 times the level you can achieve taking vitamin C orally. Maybe that explains why the original studies seemed so promising but the follow-up studies were so disappointing. This raises the controversial question of the re-evaluation of vitamin C in cancer treatment. Researchers responded to the challenge and took up the mantle, and I discuss this in my video The Role of Vitamin C in the Treatment of Terminal Cancer.


To learn more about the history of vitamin C and cancer, see Intravenous Vitamin C for Terminal Cancer Patients.

To learn more about vitamin C, see Do Vitamin C Supplements Prevent Colds But Cause Kidney Stones? and What Is the Optimal Vitamin C Intake?.

Can eating citrus protect against cancer? Find out in Citrus Peels and Cancer: Zest for Life?.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

The Vitamin C Cancer Study that Started It All

In 1975, a remarkable case was reported of a 42-year-old man suffering from a malignant form of non-Hodgkin’s lymphoma who experienced a dramatic regression of the cancer after being given large doses of vitamin C intravenously, as I discuss in my video Intravenous Vitamin C for Terminal Cancer Patients. He seemed cured, so they stopped the vitamin C. The cancer came surging back. They restarted the vitamin C and apparently induced a second complete remission. Sometimes cancer does just spontaneously regress—it’s rare, but not unheard of. So, one could argue that the first remission was spontaneous, and it was just a coincidence that it happened when they started the vitamin C. However, given the trajectory the cancer was on, followed by the rapid remission, followed by the relapse when the vitamin C was stopped, followed by a second remission once restarted, the case strongly suggests that the vitamin C had something to do with the cancer’s remission.

Now, multiple spontaneous regressions do exist. There was a recent case, for example, of a woman with cervical cancer who appeared to be cured with radiation and chemo. Her cancer came back and she refused further treatment. Yet, the tumors disappeared on their own, then came back, then disappeared, then came back, then disappeared, then came back, and then disappeared for a fourth spontaneous remission—and all that was with no apparent treatment at all. So, it’s possible this vitamin-C case is just a crazy, coincidental fluke, and the vitamin C didn’t help at all. You never know until you put it to the test.

Researchers enlisted the help of Linus Pauling, who they considered the greatest chemist of the 20th century and who was known to be interested in vitamin C. If he couldn’t get funding, nobody could get funding. And he couldn’t get funding. They went to the National Cancer Institute with promising data on the first 40 cancer patients they had treated with vitamin C and asked that the institute carry out or fund a randomized double-blind trial. In this type of trial, they would take a group of incurable cancer patients for whom medicine has nothing more to offer, randomly split them into two groups, and infuse one group with vitamin C and the other group with something like saline, basically water, and then see who lives the longest. Neither the patients nor the doctors would know who got the vitamin C and who got the saline to eliminate bias and placebo effects. The researchers and Pauling went back year after year after year asking for grants to study it themselves if the National Cancer Institute wasn’t going to do it, and they got rejected year after year after year. So, they scraped up whatever funds they could find and did their best with what they had. They published their findings in 1976.

The researchers didn’t have a controlled trial, but, by that point, they had treated a hundred terminal cancer patients with vitamin C. So, they compared their progress to that of a thousand similar patients who did not get vitamin C. For each patient treated with vitamin C, the researchers found ten patients about the same age and with the same kind of cancer who had been treated at the same hospital but who had not received the vitamin C infusions. What did they find? In patients with terminal breast cancer, within a hundred days, more than 80 percent of the women in the control group were dead. (Remember, these were all terminal cancer patients.) However, in the vitamin C group, half were still alive nearly a year later. The vitamin-C group had women with terminal breast cancer still alive 2,270 days later and counting.

The control groups for all the different cancers studied did predictably poorly, with the vast majority dead within 100 to 200 days, while the vitamin C-treated patients appeared to do substantially better. All in all, the average survival time was four times as great for the vitamin C subjects—more than 200 days compared to only 50 days for the control patients. The results, the researchers concluded, “clearly indicate that this simple and safe form of medication is of definite value in the treatment of patients with advanced cancer.” So, what happened after the study was published back in 1976?

Critics understandably attacked the study for using after-the-fact controls. One can see how this could introduce bias. If researchers consciously or unconsciously chose control group patients who were sicker than the treatment group patients, the control group patients would die sooner than the treatment group patients, but it would have nothing to do with the treatment; the control group folks may have just started out in a worse place. Indeed, there is evidence that is what happened: A full 20 percent of the control group died within a few days after being declared terminal compared to none in the treatment group, which really does seem fishy. Nevertheless, the trial was successful in finally convincing the National Cancer Institute to fund randomized controlled trials—performed by the prestigious Mayo Clinic, no less. What did they find? Find out in Vitamin C Supplements for Terminal Cancer Patients and The Role of Vitamin C in the Treatment of Terminal Cancer.


I have tons of videos on cancer, but here’s a sampling:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: