A firefighter has been unwell with frequent vomiting since attending a fire and inhaling fumes from burning plastic.
Both the patient and the GP noted that the vomit is blue. I have a sample in front of me and it is blue.
It behaves as an indicator - blue at acid pH and yellow in alkali, the colour change being repeatedly reversible.
I suspect that bilicyanin would not behave like this.
The patient is not on any drugs and is not consuming sweets.
Any ideas?
Phil