The composition of human brain tissue and brain tumors were studied by near infrared Raman spectroscopy with 785 nm excitation. The amounts of lipids, cholesterol, protein and water in fresh specimens were determined from Raman spectra by a combination of pure component spectra. Normal brain tissue was found to contain higher levels of lipids and cholesterol, brain tumors such as glioma and meningeoma displayed less lipids and cholesterol, but more proteins, in particular more hemoglobin-like molecules. These results demonstrate the applicability of Raman spectroscopy for real-time, in vivo, intraoperative diagnosis.