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History and Origin: Colloidal Oatmeal (oat flour)

Oatmeal baths have long been recommended for people with a variety of sensitive skin conditions, providing a soothing, comforting effect. The texture of colloidal oatmeal along with beneficial components such as proteins, lipids and saponins make it well suited for use in moisturisers, cleansing soaps and other products that help clean, soothe and protect the skin.

The use of oats on skin care dates to ancient Egypt.(1) Whole or rolled oats were used in soothing baths. Oats used in this way did not disperse well in baths and were messy. In 1945, technological advances permitted the manufacture of colloidal oatmeal which is prepared from de-hulled oats ground to a fine powder. The first ready to use colloidal oatmeal bath treatment was used at the Mayo Clinic in 1945. Colloidal oatmeal retains the moisturizing effects of the whole oat grain, but disperses more easily in bath water and can also be added to creams and lotions for use in topical products.

Cultivation and Harvesting

The makers of AVEENO® source colloidal oatmeal from oats (avena sativa) grown in regions that provide an ideal environment for the oat to grow, combining appropriate well drained soil and a cooler climate. Cooler temperatures and low humidity in these areas are also an advantage during storage, limiting the risk of preservation issues.


The manufacturing process for colloidal oatmeal is a process achieved without the use of chemical solvents. Oat grains with high protein content are selected for colloidal oatmeal production. Once harvested, the oats are stored in a mill elevator. The grains are cleaned to remove any foreign materials, imperfect grains, weed seeds and other grains. They are then de-hulled to remove the envelope or hull around the grains, yielding the groats.  Steel cutters are used to reduce the groat size, starting the particle size reduction process.  The groats are steam heat treated for stabilisation and to reduce free fatty acids to the lowest level. This also helps destroy bacteria and prepare the groat for rolling, flake integrity and water holding properties.

Oats contain a number of enzyme systems. Lipase is one of the most abundant enzymes in the oat. Lipase is the enzyme which causes hydrolysis or rancidity in the oat and must be inactivated to stabilize the oat. Its inactivation by steam heat reduces the release of free fatty acids, potentially irritating to the skin. Timing is critical as rancidity can be initiated within hours after the raw oat has been de-hulled. The oats are then rolled or flattened and then pulverized to the desired particle size resulting in colloidal oatmeal. This fine powder is then stored in a temperature and humidity-controlled area. The production of the colloidal oatmeal used in AVEENO® products comes from a dedicated production line assuring high quality standards.

Composition and Activity

Colloidal oatmeal is obtained from grinding the whole grain.

  • Oatmeal can help restore normal pH in skin conditions where pH has increased. In this setting, it acts as a buffering agent, thereby aiding in the maintenance of a healthy skin barrier.(4)
  • The moisturizing properties of colloidal oatmeal are provided by a hydrophilic film that forms at the skin surface. It consists of humectant and water-binding constituents and lipids.
  • Starches are important constituents of colloidal oatmeal. They are highly hydrophilic and can absorb large quantities of water.(5) Proteins contained in colloidal oatmeal further contribute to its water affinity.(7) The unique lipid composition of colloidal oatmeal(7) participates in the formation of a film at the skin’s surface.(4,8) Oat triglycerides and phospholipids, as well as oleic, linoleic and linolenic acids, which are contained in oat lipids are important stratum corneum components.(8)
  • Colloidal oatmeal provides gentle cleansing without loss of the skin’s moisture content helping to prevent skin dryness.(4)

Table 1: Components, Activities, Applications / Contents of Oatmeal


1. Miller A. Oat derivatives in bath products. Cosmet Toiletries 1979;94:72-80.
2. Rinaldi, Fabio, Rigano, Luigi. Colloidal Oatmeal, Characteristics, Properties, Clinical Applications. Scientific Library of Rydelle Laboratories; 35-43.
4. Grais ML. Role of colloidal oatmeal in dermatologic treatment of the aged. AMA Arch Derm Syphilol 1953; 68:402-407.
5. Paton D. (1986) Oat starch: physical, chemical and structural properties. In: Webster FH, ed., Oats: Chemistry and Technology. Saint Paul, MN, American Association of Cereal Chemists, Inc.93-120.
7. Peterson DM, Brinegar AC. Oat storage proteins. In: Webster FH, ed. Oats: Chemistry and Technology. St. Paul, MN: American Association of Cereal Chemists, Inc. 1986;153-203.
8. Zhou M, Robards K, Glennie-Holmes M et al. Oat lipids. J. Am Oil Chem Soc. 1999;76:159-169.

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