Dengue fever and dengue hemorrhagic fever are re-emerging diseases that are endemic in the Tropics. The global prevalence of dengue cases has increased in South-East Asia, Africa, the Western Pacific, and the Americas. The increasingly widespread distribution and the rising incidence of dengue virus infections are related to increased distribution of Aedes aegypti, an increasingly urban population, and increasing air travel. Several Southeast Asian countries show that the age of the reported dengue cases has increased from 5-9 years, to older children and young adults. Dengue infection in adolescents and adults has also been recognized as a potential hazard to international travelers returning from endemic areas, especially SoutheastAsia. Dengue is one disease entity with different clinical presentations; often with unpredictable clinical evolutions and outcomes. Bleeding manifestations in adult patients, including petechiae and menorrhagia were also frequently found; however, massive hematemesis may occur in adult patients because of peptic ulcer disease and may not be associated with profound shock as previously reported in children. Although shock and plasma leakage seem to be more prevalent as age decreases, the frequency of internal hemorrhage rises as age increases. Increase in liver enzymes found in both children and adults indicated liver involvement during dengue infections. Pre-existing liver diseases in adults such as chronic hepatitis, alcoholic cirrhosis, and hemoglobinopathies may aggravate the liver impairment in dengue infection. Fulminant hepatitis is a rare but well described problem in adult patients with dengue infection. Currently, no specific therapeutic agent exists for dengue. The early recognition of dengue infection, bleeding tendency, and signs of circulatory collapse would reduce mortality rates in adult patients with dengue infection.