BackgroundTo describe factors associated with severe sepsis in diarrheal adults and their outcomes and offender in blood and stool to understand their interplay as clinical features of sepsis and severe diarrhea often overlap.Methods and resultsWe used this retrospective chart analysis employing an unmatched case-control design to study critically ill diarrheal adults aged ≥18 years treated in ICU of Dhaka hospital, icddr,b between January 2011 to December 2015. Of 8,863 in-patient diarrheal adults, 350 having severe sepsis were cases and an equal number of randomly selected non-septic patients were the controls. Cases died significantly more (14.9% vs 4.6%, p = <0.001) than controls. 69% of the cases progressed to septic shock. In logistic regression analysis, steroid intake, ileus, acute kidney injury (AKI), metabolic acidosis, and hypocalcemia were significantly associated with severe sepsis in diarrheal adults (all, p<0.05). 12% of cases (40/335) had bacteremia.Streptococcus pneumoniae[9 (22.5%)] was the single most common pathogen and gram-negatives [27 (67.5%)] were prevailing as a group.ConclusionDiarrheal adults who had ileus, AKI, metabolic acidosis, hypocalcemia, and also took steroids were found to have an association with severe sepsis. Strikingly, gram-negative were the predominant bacteria among the diarrheal adults having severe sepsis.