The City of London police have issued a warning about the health risks posed by counterfeit makeup.

Police said Monday that imitations of brand-name makeup are often produced in unsanitary conditions. They said rat droppings and poison have been found in fake cosmetics and laboratory tests have uncovered poisonous chemicals — including cyanide and human urine — in counterfeit perfume.

They said suing such bogus products can cause skin irritation, swelling, rashes and burns and can lead to long-term health problems. They also noted that some counterfeit sun creams offer no protection from the sun.

City of London police said more than 5,500 websites selling fake luxury items have been suspended and more than £3.5 million ($5.5 million) in bogus items seized.