Doctor's Note

As I explain in my full-length live presentation on preventing, arresting, and reversing the 15 top killers (see Uprooting the Leading Causes of Death), adverse drug reactions from prescription medications are estimated to cause more than 100,000 deaths in the United States every year, making doctors the sixth leading cause of death. That’s not counting other “iatrogenic” (physician-caused) harm—such as medication errors, or infections acquired in hospitals. My profession needs to do a better job of offering fully informed consent, clearly and comprehensively explaining the risks and benefits of each alternate course of action.

The risk associated with the thallium heart scans was shocking to me. By eating healthy, we may not only eliminate the death and disability associated with heart disease, and its treatment (such as open heart surgery), but also the risks associated with heart disease diagnosis. See:

What was that about radioactive polonium in seafood? See Fukushima & Radioactivity in Seafood.

What about cell phone radiation? See Do Cell Phones Cause Cancer?

And what about getting X-rays at the dentist? See Do Dental X-Rays Cause Brain Tumors?

For further context, check out my associated blog posts: How Risky Are CT Scans?Are Dental X-Rays Safe?Dealing with Air Travel Radiation Exposure; and Ginger & Lemon Balm for Radiation Exposure.

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  • Merio

    I had a course(little) about in vivo diagnosis techniques this year… i think that were some risks but not like this… i need further study about this subject…

  • andrea

    ugh, i had at least 4 CT scans between the ages of 18-30 for kidney stones. of course i was vegan (still am) and exercised all the time, and still developed kidney stones. not fair. my risk of cancer is probably sky high. :(

    • Christo Okulian

      have you tried consuming natrium bicarbonate ?my GP doctor give his patient natrium bicarbonate for curing stone kidney. we know we can easily have it from baking powder but we have to know the dosage. i am sure many physician and health practitioner here can help u in detail. wish u a healthy life

    • Darryl

      From the cited Pearce study ( ): “For an abdominal or pelvic CT scan, the lifetime risks for children are one cancer per 500 scans irrespective of age at exposure. These absolute excess lifetime cancer risks (to age 100 years) are very small compared with the lifetime risk of developing cancer in the general population, which is about one in three”

      Ie, for those with the maximum increased risk (children younger than 18) 4 abdominal CTs would increase risk from 0.33 to 0.34 .

  • eureka1499

    As a physician I am aware of the harm modern medicine can cause to patients and also I am encouraged that somebody is speaking out. I want to learn more from you.

  • Plantstrongdoc MD

    Defensive medicine (thanks to lawyers and legislation) will only increase this problem in the future. Every doctor knows about ordering unnecessary CT and MR scans – just to avoid problems in the future (for the doctor). For every test the indication has to be right. Everything has a price. CT and MR is only to confirm your clinical suspicion. I really hate the thought that we do harm to our patients. There has to be a change, from trying to fix unfixable problems, to helping people avoid the problems in the first place. McDougall has this great picture of a man with hypertension, diabetes and high cholesterol going to his doctor. The next picture: The same man with hypertension, diabetes and high cholesterol and now he is carrying a bag full of prescription drugs! Has he become more healthy? No!

    • Coacervate

      Is it likely that even darker forces are applying pressure to use these machines just to draw in some cash flow?

      • Plantstrongdoc MD

        I understand the question; diseasecare is complicated. The doctor, the patient, false expectations, the drugs, the procedures, the politics, the money, the screening, the reductive science, the defensive medicine etc. I would advice every patient to ask their doctor what he/she expects to get out of a procedure, blodtest, CT or MR scan, PET etc.

  • citrus1

    I know this, and my daughter has had one CT scan..and many xrays..and me as well…WHAT CAN WE DO TO UNDO THE DAMAGE!!???? PLEASE GIVE US SOME ADVICE???

    • Christo Okulian

      it was mentioned that we have to eat more veggies and fruit. go back to plant based diet or in the other word become a vegan. it will enhance our self repair system, fix the damage and helps body to remove the unwanted cells (cancer cells).

    • Joe

      There are a few videos dealing with radiation exposure that Dr G has done. Particularly, lemon balm tea and ginger had a big positive effect. Also, anything that is going to help repair DNA, like veggies and especially cruciferous.

      Also, Chlorella might be very useful. Spirulina also, but as Dr G mentions, it suffers from some contamination issues. It is important to get clean, radiaiton and toxin free chlorella. CGF is associated with DNA repair.

      Also, research medicinal mushrooms.

    • Citrus,
      To reverse the damage get your health and body well nourished if you aren’t already.

      1. Opt for MRI’s,Sonograms and Thermography. If you must have X-rays ask for low radiation X-rays or CT Scans.

      2. There are ways to detox your body and protect it from radiation. I was concerned about getting X-rays due to a back injury so I went on to research and found out that protecting your DNA before and after any of those procedures is possible by juicing certain vegetables and fruits high in antioxidants (ginger, berries, turmeric etc..) and in this case radish. I have this juice here: (Please Dr. G and team let me know and I will remove this link if you feel it isn’t appropriate).

      3. By supplementing with superfoods such spirulina, radiation free-chlorella and other top supplements. I have hand picked those supplements and much more in my “natural healing shop” under Supplements on the site.

      Hope this helps!

      • Joseph Gonzales R.D.

        Hi Astrid. I would just be cautious of recommending spirulina and chlorella. Companies can not seem to get pure cultures of it so contaminated blue-green algae may be the reason why in the store, so-called pure spirulina, has toxins. For chlorella, this case study on psychosis is enough to issue caution. Chlorella appears to be helpful for patients with Hepatitis C and perhaps others, it also does not appear to produce muscle, nerve, or liver toxicity that’s been linked to spirulina, but this case on psychosis is enough to sound the alarm per Dr. Greger. I suggest supplementing with whole plant-foods and not juicing as it removed more than just fiber.

        • @Joseph Gonzales R.D.:disqus I agree with you in that we have to be extremely cautious where supplements and supefoods from. I usually do extensive research on the products I recommend. I like David wolf’s {100% Broken Cell Wall Chlorella Pyrenoidosa} and here is why: The method used to break the cell called is Pressure Differential method. The chlorella is added to a tank and the pressure in the tank is increased very high and then released and then again and again. Through this process the cell wall is reputed and the nutrition is bio-available. The same goes for their Spirulina! As with any herb, tincture, oil and even certain foods moderation and education are key. A mainly plant based diet, along with pastured organic meats, variety of safer fish along with an overall healthy life styles are the path to optimal health. Thanks for a great article ♥

  • Joelle

    What can be done if you already had a CT scan? Can the dammage be tracked? Can eating lots of antioxidants through plant foods really help or is the level of radiation too high? This video really upset me as I have had multiple CT scans and now it seems like I will most probably end up getting cancer, be it in 20 or 30 years… Is there anything that can be done?

    • b00mer

      Have you seen the videos: “Slowing the Growth of Cancer” and “Cancer Prevention & Treatment May Be the Same Thing”?

      Even thousands of years ago, before industrial waste and toxic food
      products, we still encountered naturally occurring radiation and
      carcinogens that our bodies had to guard against. Our DNA repair enzymes are working all the time and our immune system is working to extinguish precancerous and cancerous cells all the time. It’s not a matter of “having cancer” or “not having cancer”; we all have cancer! It’s really just a matter of chronic treatment and suppression. You can wait until you have a full blown tumor and throw some super potent chemo at it, or you can give any little fledgling cancers you might have started already some low-dose chemo in the form of tea, greens, onions, and mushrooms on a daily basis.

      I hope these two videos give you a new perspective and some peace on the subject.

      • Lloyd

        I’m trying to find the videos you’ve mentioned, but the site’s search isn’t picking it up. Do you have direct links? Thanks.

        • b00mer

          Hi Lloyd,

          That’s weird how the search button doesn’t pick it up. I’m always leery of putting links in comments lest they get thrown out, but if you go to the ‘prostate cancer’ tab in the alphabetical topics list on the left hand side of the page, the “Treatment & Prevention” video is on the 3rd page of the search results, and the “Slowing the Growth” video is on the 5th page. They’re great videos, a couple of my all time favorites! Enjoy.

      • citrus1

        tHANKS.I will check them out!

      • citrus1 there a best approach to fight Radiation induced cancer? are there certain supplements/food that are best suited for those exposed to excessive radiation?

    • citrus1

      Yes, it was a scary video to the MANY of us who’ve had scans..I wish the doctor would have included a plan to detox from the radiation and fight the potential for cancer

      • b00mer

        This site is filled to the brim with videos on how to fight cancer!

        • b00mer

          Under the ‘cancer’ tab, 205 videos come up. Even if half of them are about things that cause it, that would still give you over a hundred videos about treating it!

      • Jasmin boyt

        I have had two ct head scans and one brain angiogram all in space of 2 weeks as I had a bad Lumber puncture which gave a possible false read of billirubin 0.0073 just 3 over the cut off period and had to have all these tests which concluded perfectly normal but I’m worried about all the radiation exposure anyone have any advise please? Jasmin boyt

        • Joseph Gonzales R.D.

          Hi Jasmine. It is so hard to say. The best advice I feel was laid out in Dr. Greger’s video. Limit exposure when possible and eat a clean diet and lifestyle in hopes to prevent disease. If your doctor is requiring CT scans I am sure there is a qualified reason. It is important to realize the risk of “not” receiving the proper medical treatments, also. Perhaps there is a balance with preventive medicine and the ding the best we can, and diagnostic testing that although harmful, may be necessary to live. These are only my thoughts and I cannot give medical advice.

          Warm thoughts,

  • Angela

    Citrus and Joelle, I know where you are coming from. My son also had a CT scan and plenty of chest X-rays. It’s all very well to say that the best thing to do is to avoid them by staying healthy. In some cases that IS JUST NOT THE RIGHT ANSWER. In my son’s case it was a matter of life and death – he was already very sick. No amount of eating plants would have prevented him contracting pneumonia, being misdiagnosed by a paediatrician and then developing complications!

    I would also like to know how you can mitigate the risk. It has already happened. He had a CT scan. Do I now wait with baited breath for him to develop cancer? Do I watch him like a hawk for unusual symptoms? Do I not allow him to eat nasties like sweets and crisps like other little 6 year olds do on occasion? Etcetera, etcetera. FOR THE REST OF HIS LIFE? (All of which I do. And as he says to me, he wishes he were another boy who is allowed to eat what other little boys eat (and probably whose mother doesn’t go hysterical at the first sign of a illness)). I’ll admit that I am paranoid but until I discover something other than lifestyle to minimise his risks (healthy plant-based diet, fresh air, sunshine, plenty of sleep, going to a pediatrician who doesn’t hand out antibiotics like sweets), this is what I have to do to minimise his risk. IS THERE ANYTHING ELSE THAT parents like Citrus and me who are scared witless can do? Anyone?

    • b00mer

      Hi Angela, I mentioned to Joelle above the two videos “Slowing the Growth of Cancer” and “Cancer Prevention & Treatment May Be the Same Thing”.

      Our bodies are truly designed to fight cancer, provided we give them the materials they need to do the job (plants!). In short, I know of nothing specific to undo the damage of radiation that one can do after the fact, but I would watch all the videos Dr. Greger has on mushrooms, tea, greens, cruciferous, alliums, berries, etc, and know that every time you feed them to your son, you’re giving him little doses of preventative chemo. You should know you’re doing your best by him and feel good about it, especially since it sounds like the CT scan in your case was truly warranted.These plants are so powerful, especially when you look at the doses involved; half a mushroom a day, three spinach leaves a day, etc, make such an incredible difference in cancer prevention. Good health to you and yours, cheers.

    • citrus1

      Yes, Angela…You and I have the same issues here…hope to hear from the doctor soon on this! :)

  • AaronR

    It would be nice if Dr Greger could provide some information about how
    to interpret statistics for those not familiar with that topic. Many people misinterpret an increased risk of 30% for having a 30% chance to develop some disease while it means that a base risk of 1% increases to 1.3%. Which is not that much more.

    I already had one CT – Scan and the presented facts are really disturbing. But let let me just add something which might sooth one or another.

    You should always see an increased risk in relation to the unavoidable basic risk to develop cancer during live time. This basic risk is usually quite low depending on the type of cancer. And to triple a risk doesn’t mean that you are likely to develop cancer.

    Let’s say if “1.49% of men and women born today will be diagnosed with cancer of the pancreas at some time during their livetime”, than tripling this risk is still relatively low. (

    Anyway, all this is only statistics and average values. The probability of individuals scatters a great deal and if your diet is healthy and risk reducing you have a good chance that you belong to the fraction of people with fairly reduced cancer risk.

    Everything is relative. Nothing is absolute.

    • b00mer

      Excellent information! Perhaps a permanent sticky note or tag line on the subject below each video would be helpful; I’m sure Dr. Greger wouldn’t want to explain it anew in each video, but you’re right, most people aren’t statisticians.

  • Thea

    I wonder how the radiation of mammograms compares to CT scans? Even if mammograms have much less radiation, I think the risks should be determined and shared with every woman in helping them make the decision on what to do.

    Personally, the document linked to in the following paragraph convinced me (along with my doctor) that mammograms are not a good idea for most women – including me.

    “McDougall Breaking News – The Cochrane Committee now recommends against mammograms for women of all ages. Screening for Breast Cancer with Mammography – Published by the Nordic Cochrane Center 2012. What are the benefits and harms? How many will benefit and how many will be harmed? What is the scientific evidence?”

    – Source :

    • Darryl

      Mammogram doses are much smaller than CT doses – screening mammography has doses near 3 mGy total (for 2 views of each breast), wheras each adult abdominal CTs averages 14 mGy and adult head CTs averages 60 mGy.

      The Cochrane review of screening mammography was concerned less with medical radiation than with the high rates of false positives, unnecessary treatment of ultimately harmless tumors, and (in the 2012 update) negligible savings in lives from early diagnosis.

      • Thea

        Darryl: Thanks for the reply. (Sorry it took me so long to get back to this.)

        I have read the Cochrane study in detail, but was curious about the radiation doses. I appreciate you taking the time to answer that question. Very interesting.

    • Robin Rae Swanson

      I stopped getting mammograms many years ago. I have opted for thermography imaging instead. It’s not only ZERO radiation, it’s also completely painless and they usually also include your torso (front and back), neck and head. These are normally not covered by insurance, but the cost of around $150-200 every couple years is really worth saving the risk of cancer!

  • Monet

    Dr. Gregar, as a recent cancer survivor – 1st stage lung with top rt. lobectomy and no chemo/radiation, how should I think about balancing the risk of bi-annual follow-up CT scans vs return of cancer? Thanks.

    • Stay tuned for a video on what you can do to mediate your risk. Make sure you’re subscribed so you don’t miss it:

      • annie

        Dr. Greger, please could you help me with this question? is really important to me. I would like to know which are the maximum levels of kV kilov-oltage and mAs that ct machines have? and if a high kV/mAs is used during a ct exam, does the patient have symptoms? radiation exposure depends on them and Im really worried

  • Mary

    In January 2007 I had 13 CT scans after an accident, primarily done to my head. What can I do now to protect or heal myself?

  • Steve K

    My young son who is due to turn 7 later this month (December 2013) is due to have an X-ray of his skull next week here in England as he suffers from a very rare genetic disorder (Occipital Horn Syndrome) and the clinical genetic paediatricians want to look at his occipital prominences in more detail (the occipital bone is a saucer-shaped membrane bone situated at the back and lower part of the cranium). Sorry to sound naïve but does Dr. Greger (or anyone else here) know if the full mouth (panoramic) X-rays referred to here (in the accompanying video) would be the same procedure and method (and therefore present the same degree of invasiveness) as for a skull x-ray? Whilst we are or course keen to learn more about our son’s condition, understandably we have no wish to put him at risk from any other consequences from the radiation risk posed if it’s not entirely necessary. Any comments would be most gratefully received. Many thanks, Steve

  • Gayle Delaney

    No sound!

  • Greg Comlish

    It’s much worse than that. ER doctors and staff routinely pressure patients to get unnecessary scans. Once I had extreme pain from kidney stones and the ER staff wanted to get a scan, even though I brought my stone diagnosis with me as well as a CD containing the data from my last CT scan that was only a few weeks old. Doctors described the risk of a CT scan as “minimal” and nurses said the scan was “perfectly safe” and that there was “literally no risk” from a scan. I tried to say no and the nurse insisted. Then she fetched a doctor to convince me. I said “no” with total conviction and the doctor said I was “refusing treatment”(!) and tried to frighten me. They made it very difficult to not get a scan and this is typical.

    These doctors and nurses aren’t thinking at all about the damage they are causing with the radiation exposure. Their priority is covering their ass and minimizing their liability. And that means unnecessary tests and unnecessary scans. In a perfect world, doctors would be making the call about whether or not these scans are necessary. Unfortunately, for the time being, we as patients are going to have to act as our own advocates.

  • guest

    thank you doctor greger. I’m actually almost in tears at how grateful I am that you will fight against the establishment for us to bring us this kind of information. Now I know to keep my own mother away from those death machines. Time to start reenforcing a better diet plan and not a better healthcare plan.

  • Gina

    I’m getting a CT scan tomorrow to find out what is causing my severe Hydronephrosis. I don’t want to be giving myself cancer in the process. What can I do in the next 22 hours to minimize my risk? Load up on all the antioxidants I can? Already vegan (not exactly the healthiest, should eat more veggies, I’ll obviously start with that). Trying not to freak out because I know that stress depletes antioxidants as well. Gotta go make some hibiscus tea. Tips would be great.

    • Thea

      Gina: I’m not sure what you can do in a short period of time, but I think you can definitely work on long-term changes that could be of great help.

      Dr. Greger has several videos on this site that talk about the importance of cancer growth rates. Some of the information is very powerful. I may not have all the details right off the top of my head, but here is the gist of the idea: We are exposed to carcinogens all the time. Suppose you get that first cancer cell from a CT scan. No one ever died from a single cancer cell. It takes about a billion (?) cells before your body will start to register that you have a problem. So, depending on how fast the cancer cells multiply, you could actually get cancer in as little as 2 years or as many as 85 years (or more?) from now. Depending on how old you are now, getting cancer in 85 years might not be relevant…

      Clearly, how fast cancer grows is key to being “cancer-free”. While there are no guarantees, studies on this site seem to show that you have some control over how fast cancer cells grow. This is the great news. Because we are all exposed to carcinogens – not just people who get CTs.

      I hope you will take some time to find the cancer videos on this site. (I don’t have a handy list myself or I would have shared it with you.) You should be able to use those videos to figure out how to tweak your diet to make it a good long-term diet that minimizes your risk of getting cancer.

      I hope your CT scan went really well and you are able to figure out a solution to your problem. Good luck!

  • Andrew

    I have to undergo a nuclear stress test on my heart this coming week. Either that, or go back in a cath lab for another angiogram — both involve high exposure to radiation – but my cardiac symptoms are pretty severe.

    I already became a vegan when diagnosed. But, can anyone suggest REPUTABLE articles on foods, herbs, etc that I should really emphasize over the coming weeks to reduce DNA damage and cancer risk?

  • Vitor

    Hi hello, Someone that exposed high levels of radiation by repeated ct scans, can prevent a radio-induced cancer by eating health or nothing to do ?

  • Maribel

    Good morning Dr. Greger: I need to know what ‘s the risk of cancer after iodine radiation treatment for Graves Disease? Thanks!