Clinical Notes : Video guides

1. How to perform a KOH preparation

Procedure to make 100 ml of KOH 20% w/v solution:

  1. Weigh 20 g potassium hydroxide (KOH) pellets.

  2. Transfer the chemical to a screw-cap bottle.

  3. Add 50 ml distilled water, and mix until the chemical is completely dissolved, add remaining distilled water and make the volume 100 ml.

  4. Label the bottle and mark it corrosive. Store it at room temperature. The reagent is stable for up to 2 years.


Caution: Potassium hydroxide is a highly corrosive deliquescent chemical, therefore handle it with great care and make sure the stock bottle of chemical is tightly stoppered after use.

                 Republic of Ireland NOTES :