Nebulizer therapy is still one of the essential treatments employed by ENT practitioners. However, evidence that supports the effectiveness of nebulizer therapy using antimicrobial agents has been considered insufficient. Even in the latest edition of Clinical Guideline for Acute Rhinosinusitis (2010), the recommendation level for nebulizer therapy is “C1”. In our clinic, since we opened in 1994, we have basically stated important factors for nebulizer therapy as follows: (1) It shall not harm patients, (2) it shall be used as effectively as possible, and (3) its procedure shall be simple. As a result of paying attention to these factors, nebulizers used in our clinic have undergone changes over the years. Since 2003, we have mainly used small ultrasonic nebulizers for individual use with consideration of their effectiveness and safety.