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Explanation of the TILT Process

Stage 1: Initiation

TILT begins following a one-time major exposure or a series of low-level chemical exposures. Examples include chemical spills, pesticides, cleaning agents, and indoor air contaminants emitted from materials used in construction or remodeling.

Loss of Tolerance:

After an initial exposure, people who are TILTed lose tolerance for chemicals, foods and drugs that never bothered them before. Different people lose tolerance to different things, even if they’ve had the same initiating exposure.

Stage 2: Triggering

Exposures trigger symptoms, including difficulties with attention, memory and mood, gastrointestinal problems, and allergic-like symptoms. Problems are often masked so patients and their doctors cannot tell which exposures are triggering which symptoms.


People with chronic illness may be unable to link their symptoms to exposures because they are heavily “masked.” Masking results from overlapping reactions to many different chemicals, foods and drugs and normal habituation associated with chronic exposures. Until masked people reduce their overall exposures, it is impossible to know which, if any, of their symptoms or underlying health problems may be related to these exposures.

Common Symptoms

TILT-related symptoms may involve any and every organ system. Neurological symptoms such as memory problems, brain fog, and mood changes are common and often disabling. A particular initiating event (such as exposure to a sick building, Gulf War chemicals, or a pesticide) can result in intolerances that trigger multiple symptoms varying from person to person. Commonly-reported symptoms include:

  • difficulties with attention, memory and mood
  • gastrointestinal problems
  • allergy-like symptoms
  • migraines and headaches
  • fatigue and muscle pain

Common Triggers


Indoor air is the most common source of chemical exposures in many people’s lives. Moving to a new house or renovations to home or office often bring new furnishings, carpet, paint, synthetic fragrances, and pesticides. Fragranced personal care or laundry products may also be problematic for those with chemical intolerance. With the post World War II exponential proliferation of petrol-chemicals, plastics, and pesticides, people living in the modern world are exposed to tens of thousands of chemicals that humans have not co-evolved with. As a result, about 1 in 5 people in industrialized nations have chemical intolerances.


Food Intolerances are not the same as food allergies, although some symptoms may be similar. The most important difference is that allergies always involve immunoglobulins or “IgE”, where food intolerances do not. Common food allergies include eggs, cow’s milk, tree nuts, peanuts, wheat, shellfish and cause severe immune system reactions affecting numerous organs in the body.  In contrast, food intolerance symptoms are generally less serious and often limited to moderate to severe digestive problems.  Physical reactions to certain foods are common, but most are caused by a food intolerance rather than a food allergy. A food intolerance can cause some of the same signs and symptoms as a food allergy, so the two are often confused. Persons with chemical intolerance are more likely to have food intolerances rather than allergies.


Well-known drug allergies include antibiotics such as penicillin, ampicillin, and tetracyclines causing mild to severe allergic reactions. Certain drug intolerances such as salicylates (e.g., aspirin) can be naturally found in a wide range of foods, including fruits, vegetables, teas, coffee, spices, nuts, and honey; amines such as histamine, which can be present in a variety of foods including fermented foods, cured meats, dried fruits, citrus, avocados, aged cheeses smoked fish, vinegar, and fermented alcoholic beverages like beer and wine; and sulfites, which can also be found naturally in some foods like grapes and aged cheeses or added to foods like dried fruit to delay browning and wine to prevent spoilage caused by bacteria. The most common symptoms of salicylate sensitivity are: Stomach discomfort or diarrhea, Itchy skin, hives or rashes, Asthma and other breathing difficulties, headaches, fatigue and depression.

Those with chemical intolerance” are more likely to develop food or drug intolerances, although food and drug allergies may co-occur.  Your doctor is the best choice to determine whether you are dealing with a food or drug intolerance or allergy.