The presence of an increased amount of blood in a part or organ; engorgement. The phenotype is Experimental Factor Ontology id EFO_0003822 (hyperemia). Also known as: Active Hyperemia, Arterial Hyperemia, Congestion, Venous, Engorgement, Venous, Hyperemia, Active, Hyperemia, Arterial, Hyperemia, Passive, Hyperemia, Reactive.