Helmet therapy is an established method to correct positional head deformity in early infancy. Side effects such as skin erythema or pressure sores are well known for helmet therapy, but not yet adequately discussed in current literature.Retrospectively, all patient-sheets of infants treated by individual orthotic therapy in the years 2007 and 2008 were sighted and complications were noted. Complications were classified and sorted by their frequency and descriptive statistics was performed. The treatment to cure complications was recorded and success in complication control was analysed.Altogether, 410 patients fit the inclusion criteria for this investigation. Complications were apportioned into pressure sores, local ethanol erythema, unsatisfying fit of the helmet or loss of the helmet, skin infection, failed correction of head deformity, and subcutaneous abscess in one case. Non-compliance is to be noticed in a high number, but mainly occurred towards the end of the treatment period.Helmet therapy represents a safe therapeutic tool for the correction of positional cranial deformity. Complications have to be clear in number and severity for parental elucidation. Most complications can easily be avoided or eliminated by proper instruction of the parents.