I was a biology major in college, long ago. During the day plants do "breathe" in carbon dioxide and give off pure oxygen. During the night, however, they do the opposite. This is where the old rumor that plants in the bedroom are bad for your health.

At night, plants actually take in a tiny amount of oxygen, not enough to cause you any health problems- far less than having another person in your room. Another human in the room would use up far more oxygen than any plant. And I don't think you worry about the amount of oxygen your girlfriend would use if she spent the night!

The only other problem might occur if you over-water your plants- you may get fungus or mold growing on the soil. These can be bad for people with allergies. But as long as you let the top of the soil dry out before you water your plants, you shouldn't have fungus or mold.

Do not worry so much! - Granny:hippy: