Why is this pee green?

The strange side effect occurred after five days in ICU

A man with COPD presented to hospital feeling a little green around the gills, only to have his urine turn the same sickly shade in a rare reaction to his general anaesthetic.

Green urine
Photo: The New England Journal of Medicine ©2020

The 62-year-old had been experiencing dyspnoea for the past 48 hours when ED doctors diagnosed him with hypercapnic respiratory failure.

He was intubated,