Favism is a hemolytic disease due to the ingestion of fava beans in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. There is wide inter- and intra-individual variability in the development of hemolytic crisis, and several factors influence it: quantity, quality, ripeness of fava beans, and age of onset. In this narrative review of case reports and case series, we reported the predisposing factors and clinical features for four different age groups classified as follows: pregnant women and infants (i.e., exclusively breastfed children); children, from weaned to 11 years; preadolescents and adolescents, from 11 to 18 years; and adults (18 years and older). Some symptoms developed only in specific age groups: death in infants; visual impairment in children; systolic murmur in infants, children, and adolescents; and renal failure in adults. In youngest children or pregnant women the severity is the highest. Some other symptoms were present in all: jaundice, increased bilirubin, splenomegaly, hepatomegaly, discolored urine, tachycardia, pallor, abdominal pain, malaise, vomit, nausea, and dizziness. Laboratory findings are characterized by anemia, reticulocytosis, elevated bilirubin level, and sometimes urinary urobilinogen and methemoglobinemia. In most cases the symptomatology is self-limited and does not release sequelae, but hospitalization and transfusion are often required.