The symptoms of a malignant brain tumour depend on how big it is and where it is in the brain. Common symptoms include: severe, persistent headaches seizures (fits) persistent nausea, vomiting and drowsiness mental or behavioural changes, such as memory problems or changes in personality progressive weakness or paralysis on one side of the body, vision problems, or speech problems Speak to your GP if you have persistent symptoms of a brain tumour. While it's unlikely to be a tumour, it's best to be sure by getting a proper diagnosis.