Doctors in China admit they are baffled after a man began to perspire green sweat.
Cheng Shunguo, 52, of Wuhan city, says his sweat turned green in the middle of November.
"I noticed that my underwear and bed sheets were all green, and even the water in the shower," he said.
Cheng says he feels no discomfort, but went to hospital because he was worried about his condition.
Doctors thoroughly cleaned his armpits but it took only 10 minutes for his sweat to turn a piece of white gauze green again.
They have carried out blood tests on Cheng, but found everything to be normal.
"We can’t find the cause," admitted a spokesman for the hospital which reported the case to the media in the hope of finding a solution.