Aeromonas species are Gram-negative, oxidase positive, non-sporulating, polar flagellated, facultatively anaerobic rods that ferment carbohydrates. They are widespread in natural water habitats and are part of the regular flora of animals. With advances in the identification of Aeromonads, they have been described as human pathogens in a wide variety of infections. Clinical infections include gastroenteritis, the most common clinical manifestation, and extraintestinal infections with a growing frequency in recent years. The mechanism of their virulence is still uncertain. Their detection in stools can be realized with the blood agar plus ampicillin or other selective media. Acute self-limited diarrhea is shown in immunocompetent patients. Diarrhea in children and immunocompromised or chronic patients can be treated with cotrimoxazole or quinolons. Antimicrobials including beta lactam don't select for treatment because they are positive for beta lactamase.