Officials say the compound can be used as a precursor in the production of cocaine and other ephedrine-based narcotics.
The press-uz.info website quotes Health Ministry officials as saying the sale of potassium permanganate is now limited to five grams per person.
It was not clear when the restrictions were introduced.
The nongovernmental website UzMetronom reported on the new regulation on August 17, claiming authorities feared potassium permanganate could be used as a component in homemade bombs.
Health Ministry officials quoted by press-uz.info denied the claim, saying potassium permanganate is listed as a drug precursor under the 1988 United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances.
Potassium permanganate is widely used across the former Soviet Union as a disinfectant.