I have some in door plants such as Areca, peace lily and Yucca, some of them are in my bedroom as well. I know these plants produce Oxygen and remove toxins... but what about in night? do they release carbon dioxide or similar? is it safe to put them in bed room?
Yes, plants produce, just like yourself, CO2 when they burn sugars for energy. However, CO2 is not toxic, especially not in concentrations found in your house or outside. It is completely natural to produce CO2, even bacteria do it. No worries about it.
There are discussions going on about CO2 functioning as a greenhouse gas, or even that it might be responsible for climate change, this is a whole different story, since it has nothing to do with toxicity in your bed room. The CO2 here in question are produced by burning fossil fuels, they are not produced by plants.
So when there is enough ventilation in your room, there will always be enough oxygen in your room, no matter how many plants.
Hope you sleep better now? ;-)