Perillyl alcohol has previously been tested in 15 clinical studies in > 600 subjects This includes 13 studies in 255 subjects using oral administration sponsored by the National Cancer Institute and two studies in > 350 subjects using intranasal administration in Brazil. NEO100 is a highly purified (>99%) form of perillyl alcohol. Studies in Brazil suggest improved survival for patients with recurrent glioblastoma. Doses of 96 mg qid, 144mg qid, 192mg qid, and 288 mg qid administered intranasally to patients with recurrent GBM for up to 6 months, disease progression or death. From 3 to 6 patients will be evaluated after first cycle (28 days) until MTD is reached. MRI with gadolinium will be at base line, and at the beginning of even cycles. A total of 25 patients will be treated at the MTD. PK studies will be conducted during Phase 1 at first dosing, and after first dose of 3rd cycle.