Multimodal Therapy of High Grade Gliomas in Adults For chemotherapy of high-grade gliomas only few substances with proven efficacy are available. Today, even the newest substances are not proven to be superior to nitrosoureas. Although nitrosoureas are still considered as commonly accepted standard treatment, these results are based on studies in which response evaluation was not performed according to standardized criteria: prognostic criteria were not taken into account and statistical power of these studies is limited. However, a lot of questions remain to be dealt with and are currently under investigation in multicentric randomized studies. Therefore, patients should be encouraged to participate in prospectively randomized trials. With or after chemotherapy, supportive and palliative care including neurorehabilitation are important to improve patients' quality of life.