Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus.

It causes a disease called "black mold" on certain fruits and vegetables such as grapes, apricots, onions, and peanuts, and is a common contaminant of food. It is ubiquitous in soil and is commonly reported from indoor environments, where its black colonies can be confused with those of Stachybotrys (species of which have also been called "black mold").[1]

Some strains of A. niger have been reported to produce potent mycotoxins called ochratoxins;[2] other sources disagree, claiming this report is based upon misidentification of the fungal species.[citation needed] Recent evidence suggests some true A. niger strains do produce ochratoxin A.[1][3] It also produces the isoflavone orobol.