This is a pilot, observational and multicentric study of safety of sulfamethoxazole + trimethoprim + guaifenesin (Balsamic Bactrim) in adult participants with acute bronchitis. Adult participants with acute bronchitis eligible for treatment with Balsamic Bactrim will be enrolled. Administration of Balsamic Bactrim will be according to physician's recommendation under local labeling.

Inclusion Criteria:

• Participants starting treatment with Balsamic Bactrim as per treating physician's discretion
• Participants with a clinical diagnosis of acute bronchitis (cough with or without sputum production less than 30 days) according to the treating physician's judgment

Exclusion Criteria:

• Participants who have started treatment with another antibiotic at the time of the visit
• Participants with no respiratory infections
• Participants with mental disorders that do not permit the clinical evaluation of the participant according to the treating physician's criteria
• Participants with severe hepatic parenchymal damage
• Participants with severe renal failure making it difficult to monitor drug plasma concentration
• Participants with hypersensitivity to any of Balsamic Bactrim active ingredients, excipients, and/or sulfas

Adult participants receiving treatment for acute bronchitis with Balsamic Bactrim according to standard of care and in line with the current summary of product characteristics (SPC) / local labeling and who have no contraindication to Balsamic Bactrim as per the local label.