I've had many conversations with people over the last few years that experience the majority of their symptoms manifesting on the left side of the body. The discussion below about the left side of the face made me do some more searching. Every perspective in our world, when put together, makes a wheel - a relatively complete picture. Each key below is probably just as important as the others.

Incidentally, I found a few sites that mentioned when patients stopped eating wheat their left-side symptoms ceased.
I’ll assume this has something to do with spleen enlargement and the lymph’s ability to detoxify.

More pieces to the puzzle I found:
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GOOGLE BOOK SEARCH:
‘The Boundaries of Consciousness’, by Steven Laureys

'A greater involvement of the right hemisphere in emotion might account for more frequent symptoms on the left side of the body observed in some series.'

Running Energy:

GOOGLE BOOK SEARCH:
‘Soul Mind Body Medicine’, By Zhi Gang Sha

PG 190: 'Visualize bright golden or white light flowing from the right side of the head to the left side of the body.'

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PHYSICAL THERAPY/MASSAGE THERAPY/CHIROPRACTICS
Impingements or affected vertebrae can result in symptoms on one side of the body more than the other.

Nerve compression high up in the cervical vertebrae (posture, car accident, etc)
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KUNDALINI AND ENERGY LET-OFF:
When one's body is healing or working through ascension it can cause kundalini energy to radiate throughout the body. This site explains that ascension experience pretty well:

http://biologyofkundalini.com/article.php?story=ExploringtheSymptoms

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From my own studies with healing energy:

Left side of the body is feminine, Right side is masculine. Imbalances in our energy will also cause symptoms to manifest on one side or another, depending on where our lessons lie. Are you able to receive in life? Problems on the left side can mirror your ability to receive. Problems on the right side can mirror your ability to be giving.
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HOMEOPATHY: Lachesis for symptoms that tend to be worse on the left side of the body. You can read about this on any homeopathy site. I like http://www.abchomeopathy.com

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CHINESE MEDICINE:
http://www.acupuncture-services.com/basic-theory/chinese-medicine-diagnosis/t...


‘Though, the Liver is anatomically located on the right side of the body, Chinese medicine believes that the Liver is related to the left side of the body in many ways. The left side of the tongue reflects the health of the Liver. The Liver pulse is taken on the left wrist.’

TAKEN FROM:
http://www.thechinesedoctor.com/general/the-fundamentals-of-qi-energy%E2%80%A6


‘One can certainly have an imbalance of their Qi on one side of their body. In fact, it is quite common for people to have one sided problems.

And if you pay close attention to how you use your body, I am certain that you will notice differences in how you engage the left and right side of your body. Thus resulting in different imbalances.

On top of that, in Chinese medicine, we do differentiate between Qi and Blood. Classically the left side of the body is more related to Qi while the right side of the body more with blood.

So if you are experiencing a lot of right sided problems with your health, there is a likelihood that not only do you suffer from Qi stagnation, you are probably suffering from blood stagnation as well.’


TAKEN FROM:
http://www.curiouspages.com/TCM/PulseReading.html


FOOTNOTE 1 Some ancient texts state that the left side of the body is the Yang side and the right side is the Yin side. But I have always felt that this is wrong. And all my experience tells me that the left side is the Yin and the right the Yang, and all the evidence also indicates this. The Yin pulses are on the left wrist (Heart, Liver, Kidney Yin) and the Yang on the right wrist (Lung, Spleen, Kidney Yang, which are all relatively more Yang than the organs on the left, which, further, all relate to blood, which is itself a Yin substance). On the tongue, the left side relates to Yin (Liver) and the right to Yang (Gallbladder). The majority of people are right handed, with means that the right of their body is the more Yang side. All this physical evidence indicates that the left of the body is the Yin side and the right is the Yang side, and there is no physical evidence that indicates the opposite polarity—that I am aware of.
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CHAKRAS, BALANCING THE LEFT AND RIDE SIDES OF THE BODY:
Taken from: http://www.ketisharif.com/article-esoteric.html


Masculine and Feminine Principles

Integrating the body's masculine principles through structure, logic, counting and analysis will strengthen the base of the dance. Ruled by the left-brain, counted rhythm, logical floorplans and outward linear moves will facilitate the balancing of the masculine. Over-analysis, or over-concentrating from the left brain will tend to make dancers rather rigid and mechanical, lead by the right side of the body. It is very common for dancers from western backgrounds to begin and perform most moves on the right side of the body. In the Middle East however, you will notice that the dancers are much stronger on the left side and often the entire dance move is lead by the left hip. The left side of the body, ruled by the creative right brain enjoys the feminine principles of intuition, inwardness and deep feeling. Surrender, creative expression and flow are feminine and can open these intuitive channels in both men and women - in fact, any style of dance with a balance of structure and feeling can balance the masculine/feminine energies.
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NEUROLOGICAL KEYS:

Strokes point to symptoms along one side of the body.

Parkinson’s, neurological features found in Parkinson’s.
These are motor-related symptoms.

If there is damage to the right hemisphere of the brain, symptoms will be along the left side of the body.

Lesions on the right side of the brain will result in symptoms, primarily, on the left side of the body.
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