Varicella zoster virus is known to cause varicella in children and to reactivate years later as shingles. Both the primary disease and the reactivation can cause complications, both in the form of serious affection of organs by the virus itself, and through secondary bacterial infections owing to temporary immune deficiency. Relatively frequent complications include secondary bacterial skin infections, pneumonitis, complications affecting the central nervous system, and hepatitis. We describe a few typical cases seen recently in our department, and review important points connected to treatment and prophylaxis.