OBJECTIVESublingual immunotherapy (SLIT) has been considered as an effective and safe alternative to the subcutaneous route. However, different modalities and administration methods may lead to significant changes in their adherence and clinical outcomes. The purpose of this study was to compare the adherence, efficacy, and side effects of SLIT medicines: SLITone®, Lais®, and Staloral®.SUBJECTS AND METHODSEighty-two patients suffering from AR symptoms and sensitized only to house dust mite allergens were included. The patients were treated with SLITone®, Lais®, or Staloral®. Treatment outcomes related to efficacy, dropout rate, and adverse events were evaluated. The visual analogue scale (VAS) including sneezing, rhinorrhea, nasal obstruction, and itching was scored from 0 (normal) to 10 (severe), before and after SLIT. Dropout rate was defined as the number of patients who discontinue SLIT of oneself compared to the number of patients who receive SLIT.RESULTSAll of the nasal symptoms and total symptom scores were significantly decreased in SLITone®, Lais®, and Staloral®. Furthermore, there were significant difference in the improvement of rhinorrhea and TNSS between SLITone® and Staloral® group (p = 0.011 and p = 0.001, respectively). Four patients out of 26 in SLITone® group, 4 patients out of 30 in Lais® group, and 11 patients out of 26 in Staloral® group have stopped SLIT of themselves. The dropout rate was significantly higher in the Staloral® group than other two groups (p = 0.024). Only one patient complained adverse reaction such as swelling of mouth floor in the Staloral® group.CONCLUSIONAlthough all three SLIT medicines are effective in improving AR symptoms, the adherence to SLIT assessed in accordance with dropout rate was the lowest in the Staloral®.