Instruct: Classify Amazon reviews into positive or negative sentiment
Query: It really works on Cluster Headaches!!

My father has suffered from horrible cluster headaches for years. When he cannot get his Imitrex for months, due to falling in the Medicare doughnut hole, he suffers greatly. I have tried so many natural remedies for him and nothing worked, until NOW! So far Sinol has taken away 6 headaches in the first 10 days...all of them!! I've never heard him sound so happy before!! You should definitely give this stuff a try. I recommend it highly and so does my father!!!