What Is a Bluing Agent?

Bluing agents have been a common household product for nearly two centuries. The product is biodegradable and non-toxic. Bluing agents have a variety of uses, but are most commonly used to whiten clothes in the laundry. The process removes yellow tones by adding a blue tint, which can make the white appear brighter and cleaner.


Bluing agents are the result of a simple chemical process. The main ingredient in bluing agent is a finely powdered iron that appears to be a very bright blue. This iron powder is colloquially referred to as Prussian blue, and formally called ferric hexacyanoferrate. The iron is suspended in a mixture of artificially pH-balanced water, to create an entirely homogeneous mixture. Other additives include an anti-bacterial component. Despite their primarily natural ingredients, bluing agents are not safe for human consumption.


A small amount of bluing agent can be safely added to a load of washing to optimize the white tint of the laundry. The tiny iron particles in bluing agent actually dye the fabrics, hiding yellow and brown tones and making the fabrics appear whiter to the eye. There are no restrictions on types of fabric that can be whitened with a bluing agent, or how many times these items can be treated with the agent. The bluing agent has not been shown to stain or damage laundry machines.

Home and Garden

Bluing agent has a variety of uses throughout the home in garden, in addition to being used for laundry. Pet owners can safely use a very small amount of bluing agent, diluted, to whiten the fur of their light-colored dogs. Always thoroughly rinse canines after treating their fur with bluing agent. Due to their anti-algae and anti-bacterial components, bluing agents are commonly used in very small amounts to prevent unsightly green growth in manufactured ponds or aquariums.

Salt Crystal Garden

Earliest exposure to bluing agents often comes through participating in a scientific experiment with salt. Through mixing water, bluing agent, salt and optional food coloring in a well-ventilated area, large crystal-like formations can grow over the course of days. This serves as an early lesson in pH balances and chemistry for many young students, as the non-active chemical process results in rapid salt formations aided by the iron particles suspended in the bluing agent.

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