The commonest cause of Intra cerebral bleed-
Intracranial bleed

Most common cause of intracerebral (intraparenchymal) hemorrhage →   Hypertension.
Most common cause of subarachnoid hemorrhage  →  Saccular Berry aneurism.
Most common cause of subdural hematoma    → Traumatic rupture of bridging veins.
Most common cause of epidural hematoma  →  Injury to the middle meningeal artery.
Berry aneurysms
Hypertension
Diabetes
Thrombocytopenia