We need more information -- why do you need to take apart the furniture? Is the furniture old or relatively new? Do you see any nails, staples, or pegs in the joints?
My approach has always been -- if the joints are tight then there is no need to pull them apart, and if the joints are loose then you can usually pry them apart.
To take apart furniture, try using a rubber mallet or a regular hammer with a piece of softwood and perhaps a towel to keep the furniture from marring. You can also buy clamps that can be reversed so that they act to pry apart rather than clamp together.
Many paint strippers will soften the glue, but it is not always easy to get the stripper into the glue joints.
Remember, taking the furniture apart is only the first step. You still need to remove the glue from the joints.