These bright and vivid designs on T-shirts may make you swipe your credit card, but you may want to know about the hidden danger of the wears. The bad quality tops are found to contain a kind of dye that can harm your skin and health. Experts are warning customers to prewash them just to be on the safe side.

The pattern on her back could be taken as a tattoo, maybe a dragon tattoo. But no, in fact, it is the print from her T-shirt. A 24 year-old lady bought this T-shirt about half a year ago. After wearing it, she discovered that her skin was tainted by the dyes from the top. At first, she thought it would fade away after awhile, but six months later, the pattern still remained. And she's not the only victim.

In another case, a young boy who wore a T-shirt with a Super Man logo also experienced a color stain on his chest, causing him to suffer from contact dermatitis. It turns out that the chemical color stain called 3,3'-Dichlorobenzidine, is responsible for these occurrences.

We have done the test ourselves, by comparing it with another color dye of better quality. The result showed that the dye containing 3,3'-Dichlorobenzidine dissolves in warm water immediately, which is why its easier to transmit onto the skin. Experts say that harmful chemicals on human skin can cause dermatitis and can even lead to bladder cancer. To reduce the risks, doctors suggest washing clothes with vibrant imprints in warm water before putting it on.