Allergic rhinitis (AR) is a common Ig-E mediated disease of nasal mucosa, induced by an immunoglobulin E (IgE)-mediated reaction in the allergen-sensitized subjects, affecting 10% to 40% of the world population. AR could be divided into two kinds, perennial AR and seasonal AR (SAR). Allergen specific immunotherapy (AIT) is the only etiological treatment available for AR. Traditionally, AIT is divided into 2 types, subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), both of which are effective and safe alternatives.

The trial is a randomized, double-blind, placebo-controlled trial. 72 eligible SAR patients, who were sensitized to sweet sagewort (artemisia annua), were enrolled into the trial, followed by either a 32-week SLIT schedule, where the maintenance dose would be reached within 5 weeks, or placebo SLIT schedule. Standardized depot preparations of sweet sagewort (artemisia annua) extract (Zhejiang Wolwo Bio-pharmaceutical Co., Ltd., China ) were administered by means of sublingual drops.

Inclusion Criteria:

• Male or female outpatients aged 18 to 60 years (inclusive).
• With history of SAR for at least two years, with/without conjunctivitis and asthma
• Two or more nasal symptoms scores were ≥ 2 points during July - October in the last year.
• Sensitised to artemisia annua (specific IgE level ≥ 3.5 kilounit per liter).
• Patients who have been informed of the nature and aims of the study and have given their written consent, willing to comply with the protocol.
• Patients who are able to understand the information given and the consent and complete the daily record card.

Exclusion Criteria:

• Patients whose Humulus- or Artemisiifolia-specific immunoglobulin E (IgE) levels (ImmunoCAP) same as or higher than Artemisia-specific immunoglobulin E (IgE) level.
• Patients with oral diseases/ allergies within the run-in period.
• Patients accepted any kind of operations within 4 weeks of the run-in period.
• Patients applied for systemic glucocorticoids within 4 weeks in the run-in period.
• Patients with perennial AR.
• Patients with any nasal condition that could confound the results of the study (chronic rhinitis, chronic rhinosinusitis with/without polyps).
• Whatever the co-sensitization leading to clinically relevant AR, conjunctivitis or asthma likely to significantly change the symptoms of the patient throughout the study.
• Patients with comorbidity of severe asthma.