Sublingual Immunotherapy for Allergy Elimination (SLIT)

What is sublingual immunotherapy (SLIT)

Sublingual Immunotherapy (aka. SLIT) delivers a small dose of allergen daily in via allergy drops under the tongue. Allergens are things like pollen, dust and animal dander that trigger allergy symptoms such as nasal congestion, itchy eyes and sneezing. Over time, taking allergy drops improves the allergy sufferer’s tolerance. This process of desensitization is the best treatment for allergies as it eliminates the root cause of allergies not just allergy symptoms.

While anti-histamines and herbal remedies mask symptoms, immunotherapy can train your body to tolerate the allergen, eventually eliminating allergy symptoms and the need for antihistamines or allergy medicines altogether.

Your SLIT vial will contain small amounts of the offending allergen which are administered two to three times daily under the tongue. Research shows that when an allergen is presented this way, it is naturally and more readily absorbed through dendritic cells found under the tongue. This allows the patient to build up a tolerance to those allergy-causing substances.

What is the advantage of this method?
  • Just one drop under the tongue two to three times/day
  • Eliminate the need for allergy medications
  • Treat the root cause of your allergy
  • All natural ingredients
  • No painful needles
  • Much safer than allergy shots
  • Europe’s #1 Allergy Treatment
  • Proven, used for more than 15 years
  • Endorsed by World Health Organization
  • Safe for home use
What allergies can be desensitized this way?

Grass, trees, weeds, ragweed, dust, mould, cats, dogs, trees.

Allergens that are not desensitized this way are broom, cedar and horses.

The trees in the tree mixture are Alder, White Ash, American Beech, Black Birch, American Elm, Shagbark Hickory, Sugar Maple, White Oak, White Poplar and American Sycamore

How well does it work?

Sublingual immunotherapy allergy drops reduce symptoms and eliminate allergies for millions of people every year. In Europe, SLIT allergy drops represent 50% of all allergy medicine taken!

This sublingual immunotherapy is backed by more than 50 double blind, placebo clinical trials showing long term efficacy. Sublingual immunotherapy has been used for over 15 years in Europe and is recognized by the World Health Organization as a viable option for the treatment for seasonal allergies.

How long will it take for me to see results?

Typically, favourable results are seen within 30 to 60 days of treatment. However, many patients report a reduction in symptoms within the first few weeks of treatment. One study showed that within two years 85% of people were desensitized to their allergens.

Can children use SLIT?

Yes! Children three years and older can be treated with allergy drops.

Is SLIT safe to use?

SLIT treatment is a low dose, high frequency model of sublingual immunotherapy. Low dosing levels and the ease of treatment mean it is safe enough to effectively treat people suffering from chronic conditions that previously made them unable to receive allergy treatments via injection. The frequency of use is the key to this product working as such, the safety profile is excellent and there have been no reported cases of adverse reactions at this dosage.

Are there any side effects to watch for?

Rarely, however, the most common side effect of allergy drops is a mild, local irritation in the mouth and under the tongue. This usually subsides within a few days of commencing treatment. If you experience mouth, throat, chest or abdominal discomfort or if experiencing hives, itching or shortness of breath do not take further doses until consulting with healthcare provider.

Who should not take SLIT?

SLIT should not be taken by patients who are on beta-blockers or who have uncontrolled asthma. Pregnant and nursing mothers should speak to their health care practitioner prior to use. People with immune deficiencies, malignancies or autoimmune disease are cautioned not to use this product.

When should I start SLIT?

There are 2 ways to commence treatment using SLIT:

Pre-seasonal: Start treatment 30 to 60 days prior to the offending allergy season, use throughout the season and then stop. This method of treatment is with an eye toward minimizing symptoms and will be an annual treatment.

Co-Seasonal: Start treatment immediately and continue year round for two to three years. This method of treatment is with an eye toward building a permanent tolerance of the specific allergen. This means no more allergies and no more medication! Studies show that after successfully completing a full course of Co-Seasonal Treatment, SLIT users do not develop allergies again, even years after completing treatment. No more antihistamines, no more medication, just easy breathing!

How do you take SLIT?

Take one drop below the tongue using the SLIT bottle’s metered dosage pump (0.05ml) two to three times per day not right with food, drink or toothpaste. Hold under the tongue for one minute, and then swallow. Studies show that frequency is the key to the efficacy of this product. Taking one drop per day shows no change in symptoms, whereas, taking two to three drops per day shows a significant reduction in symptoms. For more information, see our clinical studies page.

Single vs. multiple allergy desensitization

SLIT drops can come in single allergen vials or Dr. Macdonald can send in a prescription to customize a single vial to include several allergens. The custom approach allows you to save time and money by having all your allergens in one vial.

  • Custom formulas can have a maximum of four allergens.
  • Mould can not be mixed in with the others. It has to be a stand alone single vial.
  • Custom formulas are prepared by a licensed pharmacist at Western Allergy in Victoria.
When to use Regular Strength vs. Extra strength formulations?

Typically you would start on regular strength for a few months and we will monitor how you are feeling. If you are still experiencing allergy symptoms you should increase the strength of the SLIT to Extra strength. Age and severity play a role when deciding as well as; a child may be fine on regular strength with no need to increase or a person whom has mild allergy symptoms may be controlled with regular strength.

How much does SLIT cost?

The price per vial is:

Custom formula regular strength: $60

Custom formula extra strength: $70

Note: Mould can not be mixed with pollens. If we need to desensitize both mould and pollens, we would need to order two sets of vials.


Shipping is charged at $15 per order. We will try to help you avoid this cost, if possible, by combining orders. It may make sense to order a few bottles at a time.

If you take the drops twice a day, one bottle will last 6 weeks. If you take the drops 3 times a day a bottle will last one month.

How many vials should I order at a time?

I suggest you start with two bottles – enough to last 2-3 months.

How long will my custom order take to arrive?

Two weeks approximately.

Contact information:

Dr. Deidre Macdonald, ND (250) 897-0235

Reference: Allergy Specific and Western Allergy Services Ltd., Victoria B.C.