How to Calculate The Dosage of Potassium Permanganate

Updated February 21, 2017

Potassium Permanganate, KmnO4, is a potassium salt which takes the form of a dark purple or black crystal powder. It is used in a number of industrial applications, as well as therapeutically to treat skin infections, superficial wounds, abscesses, skin ulcers and fungal infections, such as ringworm or athlete's foot). When used medically, potassium permanganate is always prepared as a weak solution in water, which imparts a deep magenta colour to the water. Solutions of different strengths are recommended depending on the type of infection being treated.

Calculate the amount of KmnO4 need to make a 10,000:1 solution of water to KmnO4, based on how much water you want to use. Potassium permanganate commonly comes in the form of 400mg tablets, in which case you would mix each tablet 4 litres of water (for a 10000:1 volume ratio).

Stir the KmnO4 into hot water until it dissolves completely.

Bathe the affected area(s) in the solution twice daily.

Calculate a 1,000:1 solution of water to KmnO4, or 1000 mg/litre (about 2 1/2 tablets per litre).

Dissolve the correct amount of KmnO4 in the desired volume of hot water, and soak strips of clean cotton in the solution.

Place the strips on the affected areas and let sit for 20 to 30 minutes.

Calculate a 100:1 solution of water to KmnO4 (or a 1% solution). This would 10 grams (10,000 mg) of KmnO4 per litre of water.

Dissolve the correct amount KmnO4 in the desired volume of hot water.

Soak the affected area (the feet, for example) in the solution until the water cools.


Potassium permanganate crystals are caustic, so if the dry powder comes into contact with moist skin, it may cause burns. If your skin is irritated by the solution you're using during treatment, stop using the solution and bathe the affected area in cool water. Keep the solution and dry crystals away from your eyes and mouth, and do not ingest it under any circumstances.

Things You'll Need

  • Potassium permanganate crystals
  • Bucket
  • Measuring cup with metric markings
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About the Author

After working as an editorial assistant for the University of Chicago Press, Dario Saandvik began writing in 2009. He specializes in gardening, home maintenance and computer software. Saandvik has a Bachelor of Arts in English from the University of Chicago and is in the graduate program for English literature at the University of Wisconsin-Madison.