Nightmares are caused by a lot of things and for a lot of people this information is so remote from them that they continue to have them. Stress and depression are causes that have been cited regularly. In the beginning it might seem untrue bit when you think hard about it it makes sense. Other causes that have been cited are alcohol abuse; anxiety; post traumatic stress; pregnancy; psychiatric illness and fever/fatigue. Whatever the case is dealing with these factors will help to cure nightmares.
When it comes to stress and depression and stress the best possible treatments are exercise; positive meditation; drinking water and positive affirmations. Exercise will improve blood circulation and the speedier movement of oxygen to the brain. When the brain is deprived of oxygen you have tension headaches, that's why drinking 8-10 cups of water helps a great deal.
Meditate positively on your life. Sit down and write down the nature of your nightmares. Usually nightmares stem from unfinished business in our lives. Then you should try to reverse your thoughts and focus on your nightmares in a positive light. If you're always dreaming about being arrested you should think hard about staying out of trouble.
When it comes to post traumatic stress you should strive to stem out anything that reminds you of the trauma. Avoid a place that reminds you of an accident or failure and if you're strong enough you'll benefit more if you can face your fears in the face. That way you won't have to regularly run away from things that are reminiscent of your ugly past.
What I've noted to be a good remedy is trying to visualise a better ending to your dreams. This way your mind is conditioned into resorting to that specific outcome. Thos really works when it comes to constantly recurring dreams.
For more about how to stop nightmares take a look at this simple, effective hypnosis to stop nightmares.