Sublingual Immunotherapy (SLIT): allergy drops & tablets explained

SLIT stands for sublingual (under-the-tongue) immunotherapy. A tablet or a few drops containing your specific allergen are placed under the tongue, held briefly, then swallowed. Over time, this retrains your immune system to stop overreacting to that allergen.

When the allergen dissolves under your tongue, immune cells there gradually learn to tolerate it. Instead of triggering sneezing, itching or wheezing, your immune system calms its response. The result can be lasting relief — but it takes consistency over months to years.

• Both are forms of immunotherapy and both treat the cause, not just the symptoms.
• SLIT is taken at home, avoiding regular injections.
• Studies show SLIT and allergy shots are similarly effective for allergic rhinitis.
• SLIT has a good safety record; the most common side effects are mild mouth or throat itching.

• People with allergic rhinitis (hay fever) or allergic conjunctivitis
• Dust-mite or pollen allergy not controlled by regular medicines
• Those who prefer to avoid injections
• Children and adults (specific products are approved across age groups)

The first dose is usually taken under medical supervision; after that, it's taken at home. Mild tingling or itching in the mouth in the first few days is common and usually settles. Your allergist chooses the right allergen and dose based on your test results.

SLIT works best when it's matched to a confirmed allergy — which is why testing comes first. It isn't a quick fix, but for the right person it can mean fewer symptoms and less reliance on daily medication.