HBG2 and digestive system disorder: Based on the safety considerations of HBOC-201, clinicians would pay attention to monitoring and recording AEs related to cardiovascular, methemoglobin, clinically relevant liver enzymes and pancreatic enzymes, kidney, gastrointestinal disorders, skin and sclera color, etc. Due to different clinical scenarios, the application of HBOC-201 dosage and protocols would be further explored in the future and individualized treatment of patients will be carried out to maximize potential benefits and minimize adverse consequences.