Mold is extremely dangerous; a lot more than most people imagine. Not only does mold tend to damage a lot of the objects it comes into contact with, but it can actually damage health due to toxins that it possesses. For people that have mold present, the ideal scenario would be to locate the source and destroy it sooner rather than later.
Sometimes mold can be destroyed by anyone, but usually a professional should be called. Mold such as black mold can possess some extremely harmful toxins which should be avoided at all costs. Even if the mold does not, then a lot of the time it will damage the respiratory system because of it being damp.