Assessing the clinical efficacy of weizmannia coagulans BC99 in alleviating allergic rhinitis symptoms, improving gut microbiota, and reducing adverse reactions in patients.

Inclusion Criteria:

1. Voluntarily and in writing, sign an informed consent form agreeing to participate in this study;
2. Able to complete the study as required by the trial protocol;
3. Age between 18 and 65 years old;
4. Meet the diagnostic criteria for allergic rhinitis established in the "Chinese Guidelines for the Diagnosis and Treatment of Allergic Rhinitis (2022 Revised Edition)";
5. Symptoms: Presence of two or more symptoms such as sneezing, watery rhinorrhea, nasal itching, and nasal congestion, with daily symptoms lasting or accumulating for more than 1 hour, which may be accompanied by eye itching, tearing, and redness of the eyes and other ocular symptoms;
6. Signs: Pale and edematous nasal mucosa, which may be accompanied by watery secretions.

Exclusion Criteria:

1. Use of drugs affecting the gut microbiota (including antimicrobial agents, probiotics, intestinal mucosal protective agents, traditional Chinese patent medicines, etc.) for more than 1 week within 1 month prior to screening;
2. Patients with coexisting pulmonary tuberculosis;
3. Patients with coexisting allergic asthma;
4. Patients with nasal polyps or severe nasal septum deviation;
5. Patients with severe systemic diseases or malignant tumors;
6. Individuals with congenital genetic diseases or congenital immunodeficiency diseases;
7. Regular use of probiotics or prebiotics within 6 months prior to the screening period;
8. Patients with severe gastrointestinal diseases (including severe diarrhea, inflammatory bowel diseases, etc.);
9. Individuals with metabolic syndrome (including obesity, dyslipidemia, hypertension, diabetes, etc.);
10. Patients with sinusitis, otitis media, or respiratory tract infections;
11. Individuals allergic to any components of the probiotics used in this trial;
12. Pregnant or lactating women or those planning to conceive in the near future;
13. Those who discontinue the test sample or take other medications midway, making it impossible to determine efficacy or with incomplete data;
14. Recent use of products similar to the test function, affecting the judgment of the results;
15. Participants who cannot participate in the trial due to their own reasons;
16. Other participants deemed ineligible by the researcher.