Distilled water may have chlorine in it if special steps are not taken to remove it. Distillation involves boiling water and condensing the steam into a clean container. If done correctly, the water should be cleaner, but toxins may still exist.
Distillation does a good job of removing any contaminants that have a lower boiling point than water, which is most of them. Chlorine has a higher boiling point than water, however, and special steps need to be undertaken to remove it.
There are risks to drinking distilled water as consuming it has been linked to increased risks of heart disease and cardiovascular problems. Anyone thinking of drinking distilled water regularly should consult his doctor beforehand.