Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse drug reactions (SCARs) characterized by exanthema, erosion of the skin and mucous membranes, blistering, skin detachment secondary to keratinocyte death, and ocular involvement. There are uncommon in the population but with high morbidity and mortality. In Asia has been associated HLA-B*15:02 allele as a genetic marker for SJS. In Colombia there are no data on the incidence of these SCARs, neither the relationship with potential and specific drugs or genomic studies of susceptibility genes.