Pine and Cedar bedding

Pine and cedar bedding have a chemical component (the name escapes me at the moment) which is toxic to rats. This toxicity is compounded if the bedding is not properly cleaned. It is this chemical which can (but does not always) trigger a mycoplasma infection, something my rat Indigo just had to go through. She died of this infection. For my other rat, I now use aspen bedding. I make sure to scoop out soiled bedding (i.e., where my rat urinates) every single day and I clean the whole cage out once a week (more if necessary). Ammonia build-up (from peed-on bedding which has been sitting for too long) exacerbates this infection. This is what I had to learn the hard way. I lost a rat in the process. Now I know better.