It is known that the air that we breathe contains 78% nitrogen and 21% oxygen. Even in areas where there are many trees, the content of oxygen may not be of very higher levels than the 21% that the air contains. This air does not have a detrimental effect on the lungs as is very plainly evident. Oxygen that we inhale gets incorporated in the lungs to form oxy-haemoglobin which is distributed to all the extremities of the body through the blood stream. However, the medical oxygen that is administered to patients, even with Covid-19 contains 90% of oxygen, 5% of nitrogen and 5% of argon which is also even more inert than nitrogen. Though this composition of medical oxygen is thoroughly researched and used, there is a possibility that the high percentage of oxygen content in medical oxygen is harmful to the lungs and may cause harm due to its higher percentage. A study of the harmful effects of medical oxygen has to be conducted by the medical authorities and researchers to confirm that medical oxygen is not harmful to the lungs and absolutely safe.