Hello, Welcome to HCM and thank you for your query. I understand your concern. You have an Irritable Bowel Syndome (IBS) of the diarrhoeal type. It is not due to Azithromycin and it was probably a coincidence that it occurred when you took Azithromycin. Sertaline is a Selective Serotonin Receptor uptake inhibitor (SSRI) and your response to the same is suggestive of IBS and not a diarrhoea of another cause like infection, allergy or an inflammatory bowel disease. Certain foods make the IBS symptoms worse and if you find that to be in you , these should be avoided. Eat a low residue but wholesome food, exercise and adopt stress relieving measures like yoga and relax, you would find your symptoms improve. I am available if you have further queries. Take Care Dr Noble Zachariah