Hirschsprung's disease

 Saw this on an Oxy-powder page:

There are a lot of causes of chronic constipation, and the damages caused by chronic constipation can sometime be very hard to repair. A permanently damaged bowel is called Hirschsprung's disease - which means the nerves going to the bowel have been permanently damaged or destroyed. Although conventional doctors do not diagnose it, it-s a very common disease affecting millions of people.

Not sure what to make of this.  Millions of people? The only other reference in this forum seems to infer it is a very rare condition.