Patient with dark green blood

The Lancet reported a team of Canadian surgeons performed urgent procedures on a patient who had developed compartment syndrome, they were shocked when the patient began shedding dark green blood.

In this case, the patient has taken large doses of the migraine medication, sumatriptan, that caused a rare condition called sulfhaemoglobinaemia. The patient recovered and stopped taking sumatriptan after discharge. After 5 weeks, he was found to have no sulfhaemoglobin in his blood.