In 2007, A group of Canadian specialists got a shock when they discovered green blood coursing through patient arteries like Spock from Star Trek. The medical team immedietly sent his blood samples for analysis. Results revealed, the patient had been taking huge dosages of sumatriptan, 200 milligrams per day.
This contributed to a rare condition known as Sulfhaemoglobinaemia, in which sulphur is fused with oxygen carrying haemoglobin protein in blood. This can be caused by taking excess amount of medications containing sulfonamides, another possible cause is exposure to sulfur compounds.
The man needed immediate surgery because after falling asleep in a sitting position he acquired a dangerous condition in his legs. This condition generally resolves itself with erythrocyte turnover, sometimes blood transfusions can be necessary in extreme conditions. Five weeks after his last dose, no sulfhaemoglobin was detected in his blood.