What can I do about my toddlers really bad tantrums?

I really need some advice. My son is three, and his temper is so high. No matter how little the situation may be. He scratches and bites and throws toys and hits people no matter how hard he does not care. He screams when someone corrects him. I have absolutely no idea what to do anymore. Everyone keeps telling me to take him to the doctor, but I have no idea what they would be able to do or how to stop the tempers from getting so bad.