Oxygen is absolutely essential to support the process of "vital combustion" that maintains human life. Although people can live for weeks without food or for days without water, they die in minutes if deprived of oxygen. The human body must have oxygen to convert the carbohydrates, fats, and proteins in our diet into heat, energy and life. Oxygen is the essential element in the respiratory processes of most living cells. One of the main applications of oxygen is medical and biological life support. A major oxygenation of the lungs contributes to the elimination of toxins. The more oxygen we have in our system, the more energy we produce.

Playing up on this practical theory, oxygen bars became popular during the 90s. People who enter an oxygen bar receive 50-99% oxygen from filtered or bottled water through a tube. The oxygen is inhaled for a minute or longer, and a fee of a dollar or more a minute is paid. The practice is said to be safe and enhances health and well-being by strengthening the immune system and enhancing concentration.

The downside to oxygen bars is that people who have respiratory problems are urged not to inhale this amount of oxygen, particularly if they suffer from asthma or emphysema. Also, many oxygen bars add scents to the mixture, and these scents can cause an inflammation to the lungs including pneumonia.

There are also those who say that oxygen bar treatments have no real benefits and offer a placebo effect only. Critics say that healthy people have enough oxygen in their blood and adding more does nothing at all.