This refers to diarrhoea that lasts longer than two weeks. While there is good evidence that antimicrobials are useful in management of this condition, a search should be made for non-infectious causes as well. In the ER, unless the patient appears toxic/septic, treatment should be supportive while necessary investigations are carried out, after which targeted treatment may be started, as antimicrobials would not be warranted in the myriad other conditions that can cause persistent diarrhoea (IBD, Irritable bowel syndrome, hyperthyroidism, drugs such as selective serotonin re-uptake inhibitors (SSRIs), etc.)