The bible tells us that:
Jas 5:14-18 Is anyone among you ill? let him send for the rulers of the church; and let them say prayers over him, putting oil on him in the name of the Lord. And by the prayer of faith the man who is ill will be made well, and he will be lifted up by the Lord, and for any sin which he has done he will have forgiveness. So then, make a statement of your sins to one another, and say prayers for one another so that you may be made well.
The prayer of a good man is full of power in its working. Elijah was a man of flesh and blood as we are, and he made a strong prayer that there might be no rain; and there was no rain on the earth for three years and six months. And he made another prayer, and the heaven sent down rain and the earth gave her fruit.
The bible tells us that the prayer of a "good man", one who obeys God, is powerful and effective. The scripture above also encourages us to seek prayer from the church, and it's leaders. The following is a true event off the website I list below (it is my website by the way). But don't take my word for it, if you are sick in any way, or have a friend who is I am happy to pray for Jesus to act on their behalf and bring healing.
I work as a computer programmer and have a long term client, whom I see more as a friend. While working on His website he brought up the fact that his daughter was very ill, she had developed Ulcerative Colitis, and had extreme pain and bleeding. He mentioned that doctors had told him it had no cure, and she would be on harsh medications to treat its symptoms for life. The father was saddened for his daughter, for he loved her. I having seen God heal in the past asked if he would mind if we could pray for her. He said he would appreciate it. So I set about to pray, to God for his daughter. That Sunday I also put a prayer request in the churches @SCFcentral prayer box. A month or so passed, and I received a work related call from the father. He ended the call by telling me, he did not know everything about God and healing, but his daughter was now well. So well that they were able to take the medications they were using right down. He thanked us for the prayer, and was confident that his daughter would stay well.
I have posted a link below that has some common questions with answers regarding prayer
Divine Healing | Everybody Matters Ministry