Phenols and Salicylates: What They Are and Why It Matters

Phenols are nothing more than natural chemicals made up of a benzene ring with one or more hydroxyl (OH) groups attached to it (science talk for how it is put together). They are found in many of the foods we eat like fruits, veggies, and nuts and can also be man-made for use in common non-food applications such as toothpaste, hair dyes, medicine, and disinfectants. It is important to remember that most foods have some level of phenols in them (there are many subgroups, compounds, and close chemical relatives) and that they are natural and can even be beneficial to the body, as is the case with antioxidants in fruit.

Salicylates are one type of phenol in the phenol family and scientists believe they are produced by plants for use as their own natural protection from diseases, insects, fungi, and harmful bacteria. They are made up of a phenol compound with an additional COOH group (more science talk about how it is put together). As it turns out, salicylates are chemically very similar to the man-made chemical acetylsalicylic acid, more commonly known as Aspirin.

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Dr. Feingold is probably the most widely-known individual to study this chemical, as he developed what is now referred to as the Feingold Diet. Parents with children on the Autism Spectrum are usually familiar with his work. He started out in the 1960s, as a pediatrician and allergist, studying children’s negative reactions to aspirin. Through his work, he found that many other dietary chemicals were causing physical and even behavioral reactions in his patients. He developed the Feingold Diet to eliminate all food additives, colorings, and salicylates.

Why Do People React to Them?

In a normal body, one with the correct levels of sulfates and liver enzymes, phenols and salicylates are easily metabolized. The body utilizes what it needs from the chemicals and properly disposes of the rest through the bowels. In those whose levels are abnormal, or in the case of leaky gut syndrome, intolerance to this chemical family can occur rather quickly.

Many people with gut issues, such as yeast/bacteria overgrowth or digestive diseases, can develop salicylate intolerance as a result of leaky gut Syndrome.  Leaky gut is a result of various digestive problems and occurs when the small intestine becomes too damaged to properly filter the size and types of food particles or chemicals that enter the bloodstream (for more on leaky gut read this). When these improper particles are allowed to repeatedly enter the bloodstream, the body tries to get rid of them by triggering an immune system response. Because phenols/salicylates are so common in most foods, a person with a leaky gut will have much higher than normal levels of these chemicals in their blood and can very quickly develop intolerances to these specific particles.

Why Can It Affect Children on the Autism Spectrum More?

Research by Dr. Rosemary Waring, at the University of Birmingham, found that children on the Autism Spectrum have low levels of the enzyme phenol-sulfotransferase-P (the enzyme that breaks down the phenol and amine families, also known as PST) and the substrate it uses: sulfates. Sulfates are a key tool the body uses in the process of detoxification and breaking down phenols such as salicylates. Without normal levels of sulfates in the body the sulfotransferase enzyme cannot do the task it was created to do: metabolize salicylates. So, there are two problems

Are ASD Children Affected More?

with PST deficiency: low sulfate levels and low enzyme levels. PST deficiency alone can cause problems in children (remember phenols are normal), but factor in any intestinal damage resulting in leaky gut along with it and your child’s body can easily be overwhelmed. The end result is a salicylate intolerance and the subsequent physical and behavioral reactions that come with it.

Reactions Caused By Phenols

Salicylates stimulate the central nervous system in people that react to them. This can often bring with it an emotionally extreme high followed by a very low, low. Other reactions to the phenol family can occur anywhere from immediately after consumption and up to 48 hours after the consumption of the chemical depending on the immune response. Physical reactions can include: dark circles under the eyes, red face/ears, diarrhea, headache, difficulty falling asleep at night, night waking, and in some cases excessively tired and lethargic. Behavioral symptoms of a reaction can be: hyperactivity, aggression, head banging or other self-injury, and even inappropriate laughter. Hyperactivity is more common in children’s reactions, whereas adults generally experience symptoms similar to chronic fatigue.

How Does SCD Fit In?

The tough part is that phenols, and more specifically salicylates, are found in most foods that we eat, so it is almost impossible to completely eliminate them from your diet. The most realistic thing to do is to try to only eat the foods that contain smaller amounts of the chemical by incorporating a low-salicylate diet.

SCD is great for addressing digestive imbalances which contribute to leaky gut, whereas the low-salicylate diet does not. When comparing the two side-by-side, the SCD diet can appear to completely contradict a low-salicylate diet. As SCD includes many fruits, veggies, and nuts that are also high in phenols, trying to combine the two can leave you wanting to pull your hair out. The good news is that in the beginning stages of SCD most people peel and cook their fruits and veggies, which eliminates a large portion of the chemical. To get an idea of phenol levels in foods we’ve included a few links to good phenol/salicylate food charts:



The best approach is to try a hybrid SCD diet that is low in salicylates where you become more conscience of using fruits, veggies, and nuts that contain lower levels of the chemical and see if any symptoms improve. To help with this, we looked at the amazing work of the folks at and the stages diagrams that they have published. We updated the charts to include an indication of the level of phenols in each item. They are available for free to download as a PDF here: just enter your name and email to download them. The lower phenol containing foods are at the top of each section shown with lighter colors and the phenol level increases down the list with the darker color transitions. The charts can help you to methodically introduce new foods as you progress through the diet while only using those foods that are lower in phenol content.

Over time, there is a possibility that the immune system responses to chemicals will die down. In that case, try introducing some foods higher in phenols that are only consumed every 4 days and see if the symptoms return. In some cases a four day rotation will be enough to avoid a reaction, but in others there will always be a reaction. In both situations, awareness of the chemical levels in the foods that are being consumed can drastically improve physical and behavioral reactions that might linger even while strictly following SCD.

Good luck and good health!


Jordan Reasoner

About Jordan Reasoner

Jordan Reasoner is a health engineer and author. He was diagnosed with celiac disease in 2007 and almost gave up hope when a gluten-free diet didn’t work. Since then, he transformed his health using the SCD Diet and started to help others naturally heal stomach problems. You can check out his story here and find him on Google+, Facebook or Twitter.

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44 thoughts on “Phenols and Salicylates: What They Are and Why It Matters

  1. Avatar

    If one suddenly developed an intolerance to foods with sugar most all fruits and veggies other than potato (brain fog is the main symptom) what do you do with that? Can that be healed? Makes no sense and nothing shows wrong with liver, etc.

    • Avatar

      Hi Hannah – Several food intolerances indicates a leaky gut and possible gut infections and/or hormonal issues. What we’d suggest is taking this customized quiz to get an idea of where to start:

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  2. Avatar
    Stephanie Minneti says:

    I was told that correcting glycine conjugation can help as this is the metabolic process for breaking down salicylates.

    Would taking glycine supplement help?
    It is also found in gelatin, bone broth etc.

    I find this very interesting as I also have ehlers-danlos which is a collagen defect.

    Do you have any information which could be helpful? My mother and grandmother discovered it when they stumbled across Feingold’s diet when I was a child. I am now 42. I’ve also been diagnosed with Mast Cell Activation disorder and salicylate are very high trigger for mast cell degranulation.
    I’ve had severe salicylate intolerance my whole life and through research found that phenols and terpenes are also an issue.

  3. Avatar

    Thank you for this clear and concise article on phenolics. I run food sensitivity screenings for my clients and often several different phonolic sensitivities come up. I will refer them to this article so they can better understand.

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    Grace Flower says:

    My son has had behavioral problems since 2nd grade (he’s 13 now). He couldn’t tolerate dyes, nitrates, apples, cinnamon, preservatives, Benzoates, and more. Chlorine from the pool is an issue. He would react and punch holes in walls and doors, rubbing his arms up and down, feeling like his skin was tingling, anxiety, depression, suicidal thoughts, chanting the same phrase repeatedly, he was just a mess. He developed hypersensitivity to medication, he had allergies, asthma, ADD, Learning Disabilities and anxiety that made him never want to leave the house (now we gone school). Since we learned about PST, we use Epsom salts baths, liquid zinc, b vitamins, magnesium, manganese, molybdenum and unflavored Pedialyte. The difference is amazing!!! He’s finally happy, truely happy, calm, nice. A joy to be around. No more red ears, red cheeks, horrible tantrums, even his under eye circles look better. We do a strict Failsafe Diet but he finally feels good and that’s so important. It took 5 years to get here but I’m so glad we figured it out.

      • Avatar
        Tanya du Plessis says:

        We have a similar story and the only diet that worked as grain free, dairy free failsafe. My kids are sensitive to all chemicals including salicylates, amines, glutamates, chlorine….. the list goes on. But after 2 years, we’re in a great place and the biggest skeptics have actually turned around and apologised…because our kids have a had such a dramatic turnaround. It seems our chemical sensitivity started after mould exposure in our house.

    • Avatar
      Tanya du Plessis says:

      How wonderful for your son that he has a Mom like you! It seems like you trusted your instincts and didn’t stop looking for answers until you found them. ?!!

  5. Avatar

    I stumbled upon this when trying to figure out if apples, bananas and chocolate make my son lose his *ish* for a specific reason, or if I’m “anxious mom” who makes up creazy correlations in her head. I can’t help but feel that my son has some kind of issue with Phenols. Is there a blood test to check? What should my next step be? He is 6 y.o. dx ASD and PANDAS.

    • Avatar

      Hi Jenn
      My son is NT but highly sensitive to phenols. Bananas, chocolate and vanillin (fake vanilla flavour) Block the phenol sulfotransferase enzyme and are also high in phenols. Apples are high in phenols.
      It has taken me years to work out what is wrong with my son, and I’ve finally realised it’s phenols.
      He now takes No-Fenol enzymes with meals and is 100% better. I also give him epsom salt baths to increase his sulfur and that seems to work, especially if he’s particularly toxic from an exposure.

  6. Avatar

    Hi. I just took the alcat test and found out I’m sensitive to phenols as well as all the foods high in phenols. But I’m also sensitive to glucosamine and chondroitin. Does that mean I should stop eating gelatin and bone broth?

    • Avatar

      Hi Nancy, thanks for commenting.

      Many people react to the grape juice and gelatin. We recommend you just skip it entirely, as the same nutrients in the gelatin are also in the broth.

      Another option is to mix the gelatin with water or with lime, lemon, or another plain juice you tolerate.

      I hope this helps and you’ll give the diet a try – everyone has to modify it in some way and thats what we specialize in helping people do 🙂

  7. Avatar

    So would a good test to check for this type of sensitivity to give your child a good dose of aspirin and see if they have any negative side effects from it? If not then they shouldn’t have a salicylate sensitivity?

  8. Avatar

    Yep. Phenol is simply a benzene ring with an alcohol attached to it. My best advice is to pick up a cookbook entitled “Allergy Friendly Food” co-written by Dr. Anne R. Swain, one of the top researchers on salicylates in the world. Good luck!

  9. Avatar


    I have recently been diagnosed with an intolerance to benzene, am I correct (after reading) that naturally occuring phenols could be as hazardous to my health as chemically made ones?

    Help!! Im going nuts..

  10. Avatar

    Michael….did you or your kids have food sensitivities related to phenols? Do you mind me asking if your (all of you) allergies were mainly seasonal type or if food issues were included and if so what kind? How long did it take for you to clear these problems by using Allercyl?

    • Avatar

      Hi Michael, which ones did you use for salicylate/phenol intolerance? I took a look, and I’m really interested, but my sure which would be best?! My daughter has salycilate and additive intolerance (msg/preservatives etc)

    • Avatar

      Can you email me the cheap way to desensitize the phenol intolerance? I’ve been struggling with this for 9 years before I figured out that this was causing my brain fog after eating, it’s no wonder I seems to react to everything when I thought I was eating healthy!

      • Avatar

        I’m leaving a response on the latest date on this thread. I was diagnosed with salicylate sensitivity about 10 years ago and find the blow sal diet works for me in conjunction with plenty of sunshine and steam rooms help to lower my bad reactions. I have crohns disease and have had most of my intestine removed( I have 2 out of 7 metres left if I’m right) peeling and cooking fruit and veg makes absolutely no difference to my intolerance and I still react. I eat nuts about 3 times a year as they cause reactions faster than anything other than alcohol. I was told to only drink quality champagne ( which made my husband laugh!) But it’s true. I found great relief on a combination of natural supplements including daily sulphur (msm) which can make you a very smelly person to be with?. I’m not sure anything apart from a low sal diet would work for someone in my position due to not only compromised gut but lack of it. I often get the feeling sals can also affect your eyes as mine get very red but I’m not sure that could be yet another thing crohns disease blesses me with.

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