Normally only Vulcans have green blood, a side effect of using copper instead of Iron to carry oxygen in the blood.  Iron gives Hemoglobin its Red Color, where as Copper when Oxidized is Green. 

Recently, Surgeons operating on a man were shocked to find he had green blood.

Tests showed he had taken too many of a headache pill called sumatriptan.

He was diagnosed a rare condition in which sulphur from the sumatriptan combined with the blood's haemoglobin to change its colour.

The 42-year-old smoker had needed an operation on his leg to relieve a circulation problem in Vancouver, Canada, reports The Sun.

Dr Alana Flexman, of St Paul's Hospital, said: "During insertion, we normally see arterial blood come out. That's how we know we're in the right place. And normally that blood is bright red, as you would expect in an artery.

"But in his case, the blood kept coming back as dark green instead of bright red. It was sort of a green-black. Like an avocado skin maybe.

"We were very concerned, obviously."

The man made a full recovery, and will likely live long and prosper.