To provide a medicinal composition that is capable of improving the prognosis after the restart of the patient's own heartbeat even after the passage of a considerably long period of time after the restart of the patient's own heartbeat. A gaseous medicinal composition for improving the prognosis after the restart of the patient's own heartbeat, said medicinal composition being to be administered to a human subject after the passage of at least 30 minutes after the restart of the patient's own heartbeat following cardiorespiratory arrest for at least 10 minutes. The medicinal composition according to the present invention, which contains hydrogen gas, is characterized in that a group of human patients administered with the medicinal composition shows improved prognosis after the restart of the patient's own heartbeat compared with another group of human patients not administered with the medicinal composition.
