Vitamin C Flush

Vitamin C & OrangesWhy Do We Need Vitamin C?

Vitamin C has many important roles in the body, including supporting the production of collagen within the tissues. Many of us are not eating enough Vitamin C-rich foods and sadly, our food supply contains less and less Vitamin C because of premature food harvesting, artificial ripening, and food processing.

Nobel Laureate Dr. Linus Pauling was perhaps the best known advocate of the benefits of Vitamin C. According to Pauling, Vitamin C can help fight the effects of ageing, fight cancer and provide support for healing of all the body’s cells. It may also be able to kill harmful bacteria, viruses, fungi and parasites within the body when present in sufficient concentrations. Finally, it helps fight the effects of flu, allergies and chemical exposure.

  • When damage occurs to the body, Vitamin C helps rebuild the tissue and minimise scarring associated with the injury
  • It is involved in the biosynthesis of hormones
  • It also maintains the integrity of connective tissue – cartilage, capillaries, bones and teeth
  • Vitamin C also supports the immune system – it helps your body fight infections and reduces the effects of environmental pollutants
  • An extremely powerful antioxidant in itself, Vitamin C also helps regenerate other antioxidants like glutathione and vitamin E
  • It also helps your body deal with stress

Fun Facts

Vitamin C is one of the most important vitamins your body requires and the only way to get Vitamin C is through diet. Almost all animals and plants synthesise their own Vitamin C but there are a few animals that cannot make their own vitamin C – including guinea pigs, some monkeys, a species of bat and humans.

Animals, when adjusted for human size and weight, make the equivalent of 5-15 grams of Vitamin C a day, mostly in their livers when stress free. Production can more than double when the animal is distressed (but so too is consumption by the body!). Our genetic ancestors actually once had the ability to synthesise Vitamin C but lost it millions of years ago. The enzyme that converts glucose to Vitamin C (L-3 gulonolactone oxidase) is now missing in humans. Scientists estimate that without this mutation we would be making 10-30 grams of Vitamin C a day (this is 10,000-30,000mg). This makes the RDA of just 45mg look horribly inadequate.

Why Do A Flush?

A Vitamin C flush gives our system very, very high doses of vitamin C to the point where it totally saturates the system – and in the process, brings the immune system up and supports rapid healing. This is ideal anytime you might be feeling run down, are recovering from illness or trauma/surgery, or your immune system simply needs a boost.

There are many factors which create a greater need for vitamin C:

    • increased oestrogen (are you on the pill or HRT?)
    • stress
    • infection
    • injury

Using a qualitative EEG, researchers have found vitamin C to have an anti-anxiety effect. They also discovered that less than 1000mg of vitamin C could result in an increase in cholesterol. A 2001 study published in The Lancet found that people with the lowest blood levels of vitamin C were two times more likely to die of heart disease as those with the highest levels. Interestingly vitamin C also significantly slows glycation – the process by which glucose binds to proteins interfering with their
 normal function.

Vitamin C Flush

Vitamin CThe Vitamin C Flush involves taking as much Vitamin C as your body can tolerate. When you’ve reached ‘bowel tolerance’, or the point at which you can longer absorb Vitamin C from your gut, you will experience an enema-like evacuation of liquid from your bowel. For this reason it is important you choose a day to do the flush when you can remain at home, near the bathroom.

  • Begin the cleanse first thing in the morning before you eat (you can, however, eat normally throughout the day)
  • Take 1000mg of vitamin C every hour – mix into half a glass of water (or diluted fruit juice) and drink/sip it over the course of a few minutes
  • Recording each time you take a dose – repeat this every hour, on the hour, and continue until you need to use the bathroom. You are looking for the bowel to pass a watery stool. Once this occurs, the flush is finished and you can stop drinking the vitamin C. The next time you go to the bathroom after the cleanse, your stools may still be a bit watery, but things should return to normal pretty quickly. Note what total amount of Vitamin C you took to achieve bowel tolerance*.

I like to do a Vitamin C Flush at the beginning of winter to load my immune system up ready for cold and flu viruses but you could do this biannually if you wished, and for those needing immune support/repair you could consider doing it monthly or bimonthly (under the supervision of a Natural Healthcare Practitioner). As your health improves you may notice that, each time you do the Vitamin C Flush, you need less total Vitamin C to reach bowel tolerance.

It is interesting to note that it appears the amount of Vitamin C which can be tolerated orally without producing diarrhoea, increases somewhat proportionately to how unwell you are (1,2,3,4). Most people will reach bowel tolerance at around 10-15 grams but, if the same person is acutely ill with a mild cold for example, that tolerance may increase to approximately 50 grams per 24 hours. A severe cold can increase tolerance to 100 grams; an influenza, even up to 150 grams; and mononucleosis or viral pneumonias, to as much as 200 grams per 24 hours.

Large doses of Vitamin C should always be given in divided doses, and at these higher amounts – may need to be given as frequently as hourly

Vitamin C Flush Tips

  • You must use a buffered Vitamin C powder that includes calcium ascorbate and/or potassium ascorbate – this brings the pH up (makes it less acidic) and will ensure you do not suffer from heartburn or gut inflammation that may occur when using high doses of straight ascorbic acid (the most common form of supplemental vitamin C). I personally use this one as it is buffered, super potent (1000mg in just under 1/2 tsp) and a delicious fizzy orange flavour
  • Keep your water intake up as, when bowel tolerance is reached, you will lose some fluid through the bowel
  • You may get a little bloated, or even a bit gassy towards the end – keep going until you actually pass a watery stool
  • If you have been or are unwell, you may consider doubling your vitamin C dose each hour i.e. consume 2000mg of vitamin C every hour

After The Flush

Sudden discontinuation of megadoses of Vitamin C is believed to cause ‘rebound scurvy’. Although I have only seen this once myself, it is best to be safe and gradually reduce your Vitamin C intake over several days or weeks. Here’s what I recommend the day after ‘The Flush’:

  • Work out your bowel tolerance total. Look at what total amount of Vitamin C you consumed on the day of the flush to reach bowel tolerance*. E.g. if you took 1000mg of Vitamin C every hour for 6 hours and reached bowel tolerance on the 6th dose – your total daily consumption to bowel tolerance was 6000mg
  • Take a reduced dose. The following day you want to take 75% of the total daily dose you got to before losing bowel tolerance and take this on the day after the flush in 2-3 divided doses. Using the example above, 75% of 6000mg is 4500mg which would equate to 3 doses of 1500mg each over the course of the day after the flush
  • Gradually reduce your dose. Each day take a total of 1000mg less than you did the day before. So the second day after ‘The Flush’ (using the calculations above) you would take a total of 3500mg in divided doses. The following day, a total of 2500mg and so on – until you are down to 1000mg a day (this is an ideal maintenance dose)


You can’t ‘overdose’ on vitamin C per se. Any vitamin C that is unable to be absorbed is simply passed out through the bowel. However, there are some people for whom a vitamin C flush is not advised:


  • Do not do a Vitamin C flush if you have excess iron in your blood (haemochromatosis) – Vitamin C increases the uptake of iron from your gut and we don’t want this to happen
  • Do not do a Vitamin C flush if you have Gilbert’s disease (you will know if you have)
  • If you suffer from IBS or any inflammatory bowel disease, please speak to your healthcare practitioner about whether a Vitamin C Flush will be suitable, and what form of Vitamin C would be best


  1. Thanks for the tips Amie! I was just telling Tim last night that he needed to do this as he’s got an onset of the flu (or a severe cold) coming on! Perfect timing x

    • My pleasure darling – I hope he gets better soon! X

      • Hi I have swolen lymph nodes and was wondering if it was safe to do the flush I have them in the groin and I feel it is continuing to spread

      • Hi there

        I’m sorry to hear you’re unwell; have you been to see your Dr yet? There are a few things that may be causing the swelling in your lymph nodes and it is very important that you have that medically assessed as soon as possible.

        If the swelling is a secondary result of an infection, a vitamin C flush (amongst other support, not just on its own), will be helpful.

  2. Thank you so much for this Amie, our entire household has been fighting a viral throat infection type thing two of the six in the household have been on antibiotics and still haven’t gotten over it. So this weekend we will all be doing the flush x

    • Oh nooooo – that’s not good news Erica! I hope the flush is going well and that you all bounce back soon. I’m sure you would already have organised this but don’t forget to get straight onto some probiotics as soon as the antibiotics are finished. You might also want to consider some Zinc and Vitamin D too. Wishing you all a speedy recovery X

  3. Thank you Amie for this article. I’ve been experimenting with high doses of Vitamin C a few times, but I’ve just found your website, and discovered that it is contraindicated with Gilbert Syndrome. Can you please explain why? I’ve Gilbert Syndrome and I didn’t notice anything strange while taking the Vitamin C to bowel tolerance. Also Gilbert Syndrome doesn’t give me any symptoms, just high bilirubin in a blood test. Thank you!

    • Hi Giuditta – the issue is only that high doses of vitamin C may give a false negative reading of urinary urobilinogen if you’re trying to diagnose it.

      Having already been diagnosed with Gilbert Syndrome, optimal vitamin c levels will only be useful for you!

      • I started the flush early this morning at 7:30.
        It’s 1:22 am niow.
        I did not have diariea until about 10:00 pm tonight .
        I have taken a 1/2 tsp every fifteen minutes.
        And before the flood gates opened. It was INTENSE cramping!
        I was told to keep taking it every 15 minutes until clear watery stooka.
        I’m confused how much I need to take in the morning.
        I have so far taken 36 tsp .
        What does that come to for tomorrow

      • Hi Deborah

        What flush are you doing, and with what product?

  4. Dear Doctor Amie,
    Thank you for your immense insight on the power of this molecule; Ascorbic Acid. Would you please do s

    • Hi Dr Hunter – thank you for your kind comment. I’m afraid your message appears to have been cut off so if there was anything further you’d like me to respond to please reply 🙂

  5. Question re VitC flush – can it be used (adjusted) as pre colonoscopy prep – has to be better tasting than the prescribed preps which are so bad they put you off having regular checks even tho they are necessary.

    • Hi Linda – it would be best to check with your specialist but I am almost certain it wouldn’t do the same job.

      There is another version of the flush which is designed to induce a laxative effect (and as such you will get bowel clearance) however it works by creating an osmotic gradient. What I mean by that is water is drawn into the bowel, creating the laxative effective.

      I don’t believe, however, that it would soften any hardened/trapped faecal matter (and move it along) like a prep kit does. The preparation that they use also has a stool softener and a peristaltic in it, which guarantees a complete emptying of the gut. This is absolutely necessary in order for a colonoscopy to be performed.

      Sorry I don’t have better news…

  6. Hello,
    Thanks for your article. Can the flush be done with pill form vitamin c?

    • Hi Amy, great question.

      Given the time it would take for the tablet/capsule to dissolve and then be absorbed I don’t think it would work anywhere near as well – sorry 🙁

  7. Thanks so much for the information! I did a flush today and then happened to get a call from my doctor with blood work. My iron levels are elevated. I don’t want to stop the vitamin C immediately, as it took me 50 grams to reach bowel tolerance. However, I don’t want to develops curvy either. Do you have any recommendations?

    • Hi Chris,

      I can’t give you individual advice as I don’t know your case but my initial questions are:

      – what did your Dr say when you asked them about it?
      – what day are you at on the vitamin C flush (what daily dose are you taking)?
      – how elevated are your iron levels, and has the cause been identified?
      – what treatment has been proposed, if any?

      My first recommendation, if you haven’t done this already, is speak to your Dr.

      In the meantime, you could potentially reduce your daily vitamin C levels by 2-3g/day (rather than the typical 1g) to get back to baseline quicker whilst reducing the potential for rebound scurvy.

      Further to that, vitamin C does not increase iron levels per se but it does increase iron absorption from iron-containing foods in the gut (by 30% according to the evidence I’ve seen) so if you were not consuming any dietary iron it would not boost your iron levels any further. Were you advised to avoid all iron-containing foods?

      These are worth looking at too:

      Wishing you all the best.

  8. Amie, I see you also say to start w/ 1000 mg which is .2 tsp. How does one measure .2 tsp? I see 1/4 tsp is 1250 mg and that is easy enough to measure, so why do most sites recommend 1000 mg?

    • Hi Sue

      The amount of powdered vitamin C to deliver 1000mg will depend on what brand you buy.

      I personally use BioCeuticals Ultra Potent-C and 1 level metric teaspoon gives 4g of the powder, of which 2.45g is vitamin C (or 2450mg). For convenience sake, I just use half a teaspoon each dose knowing that I’m actually getting 1225mg each time.

      The key is to use a close approximation of 1000mg per hour, and to ensure each hourly dose is identical to the last.

      This means for example, you may end up calculating your overall daily intake (and subsequent titration down over the following days) in half teaspoons.

      Hope that makes sense?

  9. I only suspect I might have IBS would it be okay to do this? What could I potentially expect if I do have IBS?

    • Hi Debbie

      If you are having gut issues it is best to have that investigated and diagnosed before introducing anything out of the ordinary. If your gut is inflamed, for whatever reason, using high dose vitamin C (especially if it contains the ascorbic acid form) may potentially have an aggravating effect.

  10. Can one use this flush if they have an autoimmune disease

    • Hi Rose

      If you have an autoimmune condition, you will need to speak with your healthcare practitioner about whether the vitamin C flush is appropriate for you. They will be able to take into account your medical history, any medications, and unique physiological make-up to determine whether this is suitable for you or not.



  1. How Sugar Disables Your Immune System – What The Naturopath Said - […] to you. If you are currently dealing with a respiratory tract infection, ask them whether or not a Vitamin C…

Submit a Comment

Your email address will not be published. Required fields are marked *