Clinical Cases

Post-COVID Fatigue and Headache Resolved with Polarity Analysis

Homeopath Karen Allen discusses basic principles of Dr. Heiner Frei’s Polarity Analysis and presents a post-Covid case to illustrate.

As the global COVID-19 experience flows into its third year, our clients continue to seek support. Sometimes they consult us during an acute COVID illness; oftentimes in my practice, clients are reaching out in the weeks   after the initial phase of the illness has passed.

They request help with post-COVID symptoms that have not cleared in the intervening time period. In this article, one of these ‘sequelae’ cases is shared. The case was analyzed using Polarity Analysis, and had a prompt resolution. It provides a window into some of the unique advantages of using Polarity Analysis in day to day clinical practice.

Polarity Analysis uses “Polar Symptoms”: Boenninghausen’s Legacy

In 1827, Clemens Maria Franz von Boenninghausen was near death. A botany colleague named Carl Weihe, who also practiced homeopathy, suggested that he take Pulsatilla which promptly cured his tuberculosis. Surprised and inspired, Boenninghausen pursued the study of homeopathy.

He became Samuel Hahnemann’s closest student and colleague. Although he never attended medical school, Boenninghausen was granted the authority to practice medicine by the King of Prussia. From 1843 until his death in 1864, he attended patients in his practice each day from 9am to 2pm. His extensive clinical experience brought him to some practical conclusions about what worked (and what didn’t).

Boenninghausen observed that some remedy pictures included opposing symptoms within their patterns. Hepar sulph, well known for aggravation from open air or cool breeze, also showed amelioration from the same condition. The proving of Natrum muriaticum produced both an increase of hunger and an absence of hunger.

Belladonna’s materia medica included head pain symptoms that were improved by having the eyes open, and also improved by having the eyes closed. He called these “polar symptoms” because both poles of the same symptom continuum were present in the provings or clinical case work.

Over time he observed that, while both of these opposing modalities were present, one polarity was almost always much stronger than the other. In his clinic, he realized that when he selected a remedy for a client using the symptom of the stronger pole, the outcomes were consistently more successful.

According to his writings, he became convinced that remedies selected based on the indications of the weaker poles would not     lead to cure. This information was well documented in Boenninghausen’s writings and case work, where it awaited a time when modern homeopaths would leverage this reliable guideline of success.

Heiner Frei Brought Visibility to “Polar Symptoms”

Swiss pediatrician and homeopath Heiner Frei and his colleagues used Boenninghausen’s Therapeutic Pocketbook in their daily case work for decades. In order to assess and improve their results, they audited their  client reports.

They iteratively reviewed thousands of repertorizations and outcomes. Case by case, they looked for rubrics that were most reliable for an accurate remedy choice; they also identified the red herrings that were more likely to lead to an incorrect choice.

They gathered and summarized statistics, gradually identifying the usefulness and strength of each of the rubrics in the Therapeutic Pocketbook. They confirmed the reliable and consistent outcomes of cases where Boenninghausen’s ‘Polar Symptoms’ were used.

Based on the clinical importance of these “polar symptoms,” Dr. Frei eventually designed a software tool that highlighted Boenninghausen’s strong and weak polarities. He also incorporated the ratings of higher or lower reliability for the individual Pocketbook rubrics based on the clinical tracking that had been completed with his colleagues. He named the software and method of use ‘Polarity Analysis’. For the first time, an average working homeopath had clear visibility of Boenninghausen’s guidance on stronger poles!

Heiner Frei’s work was first introduced to this author during a Liga presentation in 2014. In addition to the explanation of the approach in his lecture, he also provided an early version of the Polarity Analysis software on a portable jump drive to all of the interested attendees. Since that time, a version of the software was also introduced into RADAR homeopathic software package.

The current software version is hosted online at, which offers a free trial and subscription. The following cases examplify the Polarity Analysis method and include repertorization charts from Dr. Frei’s ‘Polarity Analysis’ software.

Post-Covid Case (5.5 weeks): headache, fatigue, and brain fog (68 yo male)

This returning client requested an appointment after several years’ hiatus. In the past, his primary complaint was anxiety and stomach pain, which had successfully resolved with Magnesium carbonicum. He had enjoyed  good health until February 12, 2022, when he tested positive for COVID-19.

During the acute phase, he “felt flu-ish” with some fever and chills. After a few days, he developed a light cough, which disappeared within a week. After 10 days, he had none of the acute symptoms, but did not feel well. During the subsequent month, he did not bounce back to his usual state of health.

In an online consultation on March 16, 2022, we reviewed Dr. Frei’s ‘Checklist of Reliable Symptoms’ together. The client’s chief complaint was overwhelming fatigue and a vague achiness of the head that had been present continually since the acute COVID episode. He reported:

“I have never felt this weary. I wake up and feel awful – the worst I will feel all day is when I first wake up. In these past several weeks, I have become much more sensitive to noise, and the ticking of the clock in the bedroom hurts my head when I wake up.”

“Each day I have to consider carefully what I must do, so that I do not overexert. I have whole days where I am on the couch. When I do too much, the symptoms are  much worse the next day.”

“Any physical effort makes the sore aching in the head worse, and I get very irritable, shouting at the dog and my wife over nothing. It becomes impossible to think, hard to understand what is being said to me.”

After any exertion, such as standing to prepare a meal, or climbing a flight of stairs, his energy drops. He is averse to any movement or activity, and he feels relieved when he is laying down.

“Laying down with my eyes closed helps right away. I have to   close my eyes. As soon as I lay down, I get relief with the head, the irritability, and the fatigue. After I have rested for an hour or two, I can get up and do a little. I often get up to eat. I have been much more hungry than usual since I had COVID, and am eating more food, more often.”

Upon review, these were the client’s symptoms to be included in repertorization:

  • Aggravation from physical effort (normal daily activities)
  • Aversion to movement
  • Difficulty thinking, comprehending
  • Aggravation on first waking in the morning
  • Improved by laying, by resting, by closing the eyes
  • Relief very quickly upon laying
  • Increased hunger, and increased irritability
  • Increased awareness and aggravation from noises in his environment (clock ticking)

Reading a Polarity Analysis Chart: useful hints and handy features

Using these symptoms from the client’s report, the following repertorization was created with the Polarity Analysis software. The resulting chart is recognizable as a repertorization, though it contains some unique features:

  • Boenninghausen identified the reliability of polar symptoms, marked with a ‘P’ to the right of symptom text. Not all of the entries in Boenninghausen’s Therapeutic Pocketbook are “Polars”. The software makes it clear which ones are or are
  • A “reliability rating” is given with a color block beside each rubric, based on the findings of Dr. Frei and his colleagues in their decades of case reviews. In this chart, most of the color blocks are These are reliable rubrics.

One rubric (aggravation from noise) has a yellow color block. It is considered somewhat reliable, not a sure bet, probably due to its smaller size. In his Polarity Analysis textbook, Dr. Frei recommends use of green rubrics, with minor inclusion of yellow rubrics to be used with some caution. (There are also rubrics flagged with a red color block, and these are to be avoided as unreliable).

  • A red line divides the chart in half horizontally. Above the red line, the selected symptoms are graded 1 though 5 for each remedy shown, with 5 being the strongest match in proving and clinical Below the red line, the software provides visibility of the opposites of the polar symptoms. In the chart below, notice that the rubric about noise is not flagged as a polar symptom, and has no opposite in the lower half of the chart.
  • White or Grey shaded columns (right side of chart) are titled with each remedy

!  In this chart, the first remedy listed is Nux vomica. Our client reported increased hunger (grade 2 for Nux Vomica) following the acute COVID onset. Below the red horizontal divider in the chart, the polar opposite symptom of absent hunger (grade 4, stronger in proving and clinical case work for Nux vomica) is listed. Thus, the client exhibited the weaker pole of this Nux vomica symptom. Based on Boenninghausen’s guidance, this remedy would be an unlikely success. The symptom is   marked with ‘CI’ (contraindicated), and the column is shaded gray as a visual cue to avoid that remedy.

White columns show remedies with no contraindications; these are likely considerations for     the client. The visibility of these remedies with no contraindications is a major advantage. The homeopath can focus the materia medica differential on remedies that Boenninghausen would suggest have the greatest chance of success, saving time and effort.

Based on the results in this chart, the remedy most strongly suggested for consideration was Coffea cruda.  In his training materials, Dr. Frei emphasizes selection of the appropriate remedy through the strength of the polarity comparison, as well as the coverage of the majority or all of the rubrics.

Coffea cruda had both a high polarity and thorough coverage in this set of rubrics. It was an unexpected remedy to appear in this terrain of post-viral  fatigue and headache. This often happens with Polarity Analysis where there is an opportunity to learn materia  medica in an unexpected presentation.

Investigation of materia medica references for Coffea cruda showed confirmation of symptoms:

  • (Clarke’s Dictionary) “Coffea belongs to the same family as China, Ipecacuanha and like these remedies has many symptoms of intermittent fever. It has been noticed that coffee drinkers who do get fatigue are more difficult to cure than those who do not drink coffee.” “Pains in the head as if the brain  were ”
  • (Guernsey) “It is at the front of the rank of remedies for ”
  • (Hahnemann) “Patients look exhausted, retire to dark places, close their eyes to avoid light of day; remain seated in an armchair or stretched on a The least noise or motion excites the pain.”
  • (Hering’s Guiding Symptoms) “Hearing more acute and sensitive.” “Morbid sensation of excessive Increased hunger with hurried eating.” “Worse from bodily exertion.” “Great sensitiveness and pain of affected parts.”
  • (Farrington’s Clinical Materia Medica) “There is heavy, dull aching in the head, which is worse from reading, thinking or any use of the ”

Based on this assessment, the client was asked to take Coffea cruda 30c (available from local store) daily for     3 days, and then report response after 5 days.

“The response was almost immediate,” the client reported, “with my energy coming back. I have had no more days on the couch, and my mood is much better. I am able to think clearly. I wake in the morning feeling rested now, without the head aching, and without the noise sensitivity. My appetite is also back to normal.”

The client was asked to repeat the dose if symptoms back tracked, but later reported that there was no need. At a 4-week check-in, there were no remaining symptoms from the Post-COVID experience.

Chart for Case 1: Post-Covid (5.5 weeks): headache, fatigue and brain fog (68 yo male)

The client’s symptoms were matched well with a remedy that brought speedy relief. Heiner Frei’s Polarity Analysis method allows the Vital Force’s expression of symptoms to be gathered and assessed in an efficient and reliable manner. In this author’s experience, the accuracy of this method extends to both acute and chronic cases in a wide variety of complaints and client populations.

For those who may not have tried this approach, consider learning a little more, and trying it with any cases where you have not had success with other methods! There is a lot of training information on Heiner Frei’s website and YouTube channel; the Polarity Analysis software offers a free trial. There is also a 3-month training course taught by Tim Shannon, ND, DHANP, which includes theory, live clinic, and case supervision.

Karen Allen CCH directs the Trinity Health Hub, a virtual resource for homeopaths around the world. You can learn more about her at

Heiner Frei MD‘s website for Polarity Analysis, including his research studies, is:

About the author

Karen Allen

Karen Allen CCH is a nationally awarded and certified classical homeopath, with 28 years of clinical experience. A graduate of Texas A&M University, she worked in the information technology field until a difficult illness for one of her children was resolved with homeopathy. After retraining in homeopathy, phytoembryology, counseling and hypnotherapy, she began professional practice in 1994. Karen was a Bastyr University adjunct faculty member, teaching homeopathy (2001 – 2007), and later a faculty member at Phoenix Institute of Herbal Medicine and Acupuncture. She presents at conferences nationally and internationally, and has authored two widely used homeopathic textbooks. Strongly committed to the integrative healthcare emerging professions, she is a past president of the Council for Homeopathic Certification, a national credentialing body for the homeopathic profession. She formerly served as education director for Homeopaths Without Borders. She is also a past board member for the Integrative Health Policy Consortium, an advisory body that provides guidance for legislators and government regulators on health policy.


  • Thank you Karen, that was a very clear and succinct explanation of Heiner Frei’s Polarity Analysis. Polarity simplifies some cases that would otherwise become needlessly complex.

  • Thank you Karen. The method looks simple and replicable, features that are needed in an effective therapeutic system.

Leave a Comment