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Microscopic colitis (MC), collagenous (CC) and lymphocytic colitis (LC), the cause of chronic secretory diarrhea, is very likely secondary to an inappropriate immune response to an intraluminal antigen occurring in a genetically predisposed subject. The origin of this immune dysfunction is currently unknown but various triggering or promoting factors such as drugs have been widely discussed. The 3 main therapeutic classes associated with the occurrence of MC in many cohort or case-control studies are proton pump inhibitors, nonsteroidal anti-inflammatory drugs and selective serotonin reuptake inhibitors. Other drugs, implicated in clinical cases directly reporting a causal link between the drug and CM, were analyzed using the algorithm developed by Beaugerie et al. and the imputability of each drug was evaluated. The initial management of a CM imposes to eliminate an associated celiac disease and a drug cause. Any drug started in the 4 months preceding the onset of diarrhea should be suspected, its withdrawal leading to clinical improvement in a few days and the disappearance of histological lesions in a few weeks.