Carbon monoxide (CO) is a colorless, odorless gas that can cause severe illness and death after inhalation. After entering the bloodstream, CO replaces oxygen on hemoglobin, reducing oxygenation to peripheral tissues. When CO poisoning is associated with lung injury, treatment with 100% oxygen might not be effective. Leveraging previous studies showing that visible light was able to dissociate hemoglobin from CO, now, Zazzeron et al. developed an extracorporeal membrane oxygenator for blood exposure to visible light. The use of extracorporeal removal of CO using phototherapy, increased CO removal compared to 100% oxygen inhalation in rat model of CO poisoning and increased survival when CO poisoning was associated with lung injury.