Several of the acute diseases with infectious etiology (viral, bacterial or parasitic) initially start with a syndrome which can be febrile, febrile icteric, febrile hemorrhagic, febrile with respiratory manifestations, febrile with neurological impairment, febrile with dermal eruptions, febrile anemic, diarrheal, necrotic cutaneous ulcer, or deaths of febrile patients may occur without a defined diagnosis, with some variants according to the ecological-social niche in which they occur; the syndromic approach is important, to quickly classify the case or the outbreak and thus have an appropriate and timely diagnosis that allows to orient both the individual management and the prevention and control measures in the population, even if there are limitations for the diagnosis of all the cases. This article describes the syndromic approach, the syndromes of importance in public health (collective) and their approach, all this is important because of its presentation in outbreaks that are occurring in the various ecological niches of our country, exacerbated by climate change.