Abstract: The present invention provides a therapeutic and/or preventive agent for coronavirus disease 2019 (COVID-19) comprising 5-aminolevulinic acid (ALA) or its derivative or a salt thereof and provides a method for treating and/or preventing coronavirus disease 2019 (COVID-19) using the therapeutic and/or preventive agent.

Abstract: An agent for ameliorating and/or preventing sickle cell disease, includes 5-aminolevulinic acid (ALA) or a derivative thereof or a salt thereof. The agent is useful for amelioration and/or prevention of sickle cell disease. The agent may include one or more kinds of metal-including compounds. The metal in the metal-including compound can be any of several different metals, including iron, magnesium, zinc, nickel, vanadium, copper, chromium, molybdenum, or cobalt.

Abstract: The present invention relates to the therapeutic use of compositions containing 5-aminolevulinic acid for the local treatment of inflammatory bowel disease, including but not restricted to ulcerative colitis and Crohn's disease.

Abstract: Provided are an agent for preventing and/or treating a flavivirus infectious disease and a method for preventing and/or treating a flavivirus infectious disease. At least one selected from 5-aminolevulinic acid (5-ALA), a 5-ALA ester, a salt of 5-ALA, or a salt of the 5-ALA ester is used in the agent for preventing and/or treating the flavivirus infectious disease. Examples of the flavivirus to be prevented or treated by 5-ALA or the like can include dengue virus, Zika virus, Japanese encephalitis virus, tick-borne encephalitis virus, West Nile virus, and yellow fever virus.