Stop the overflow
Shut off the toilet's supply valve if that is appropriate and safe, and avoid repeatedly flushing a blocked fixture. A plumbing problem should be corrected before the area can be considered stable.
Consider contamination
If the overflow contains sewage or has contacted waste, keep people and pets away and treat the area more cautiously than a clean-water spill.
Look below the surface
Bathroom water can seep around flooring edges, under baseboards or through penetrations into the level below. Moisture checks can help identify how far it traveled.