House plants are good for some nature therapy, especially in the winter months when it is cold, snowy, etc. for many people. They are beneficial because photosynthesis is the process by which green plants use sunlight to synthesize foods from carbon dioxide and water. During photosynthesis, the plant absorbs carbon dioxide (we breath out carbon dioxide) and releases oxygen (we breath in oxygen). Plants help to increase oxygen levels, which is good for us other living creatures.