The goal of this clinical trial is to validate the effectiveness of the modified olfactory training device, the main questions it aims to answer are:

Is it possible that the device can treat olfactory disorders in adults? Compared to the conventional device, how efficient is the modified olfactory training device for treating patients with olfactory disfunction?

Olfactory training is a new therapy that improves olfactory function by exposing patients to various types of odors through regular, repetitive active sniffing. However, there are still many problems with olfactory training in clinical practice, including poor patient adherence, lack of standardized and uniform procedures, and inconvenient carrying of devices.

Now, the investigators have initially developed an olfactory training device based on expiratory pressure, and the advantages of the improved device are as follows: bi-directional airflow, positive pressure and the function of voice prompts and automatic counting.

In this study, the investigators planned to recruit 72 patients and divided them into two groups for olfactory training with conventional and modified devices, and validate the effectiveness of the modified device based on the comparison of the outcomes of the two groups.

Inclusion Criteria:

1. Patients diagnosed with olfactory disorder when TDI score was less than 30.75.
2. Patients would perform Sniffin' Sticks examination.
3. Voluntarily sign the informed consent form
4. Able to undergo olfactory training and participate in follow-up visits

Exclusion Criteria:

1. Smoking
2. Combined with chronic diseases, such as hypertension, diabetes, bronchopneumonia, chronic obstructive pulmonary disease, etc.
3. Those who have taken oral glucocorticoids, antibiotics, anti-leukotrienes, and antihistamines within four weeks will be excluded.
4. Patients who cannot tolerate olfactory function testing and treatment
5. Severe coexisting diseases: such as malignant tumors, life expectancy <2 years
6. Patients who are pregnant or planning to become pregnant
7. According to the researcher's judgment, the patient is unable to complete this study or cannot comply with the requirements of this study (such as memory or behavioral abnormalities, depression, heavy drinking, past breach of contract)

We will decide whether to share the individual participant data after the study.