Blue-green algae, such as Aphanizomenonflos aquae (AFA) or Spirulina {Arthrospira) can be fractionated. Anti-inflammtory aqueous fractions of blue-green algae are described herein that include low molecular weight molecules. Methods for reducing inflammation in a subject are also described. These methods include administering to the subject compositions comprising a therapeutically effective amount of the anti-inflammatory aqueous fraction blue-green algae, or dried form thereof, thereby reducing inflammation.
