One of the reasons why plants are so good for your home is that they absorb carbon dioxide from the air, and release oxygen in its place. This takes place during the day when the plant is actively photosynthesizing. At night, many houseplants absorb oxygen and release carbon dioxide. Some homeowners, especially those with sleep apnea, may worry that the plants can "rob" them of the essential oxygen in their bedroom. This fear is understandable but invalid. Having a few plants in your bedroom won't increase your carbon dioxide levels enough to cause harm. Plus, there are some plants that photosynthesize even at night, releasing valuable oxygen into the air. The Snake Plant is one of those plants, as are the Aloe Vera and Spider Plants.