Please, could you answer this question a new sister has asked me. I told her that it was a question for a scholar. Your reply is most urgent.
Question:
I am very sick right now, and no one knows what is wrong, if it is something deadly like cancer is it ok that I don't take the medicine that might help me. says:
إنـك لا تهـدى من أحببت ولكن الله يهـدى من يشـاء
And refuse the surgery.
I realize that you have many questions to answer please could you answer this? May Allaah reward you all (the Arabic is the title she was using, I spoke with her on messenger)?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

First of all, we ask Allaah to cure this sister and grant her well-being. We advise her to be patient and steadfast on Islam and not despair from Allaah's Mercy because of the disease that she has, as patience is the solution to every difficulty. It is confirmed that the Prophet said: "How strange is the matter of a believer, there is good in all his affairs, and this is only for the believer. If something good happens to him and he is grateful, then this is good for him, and if a calamity befalls him and he is patient, then this is also good for him.” [Muslim]

Furthermore, we advise her to supplicate Allaah as much as possible and to think good of Allaah.

The most preponderant opinion of the scholars is that it is permissible to seek treatment from a disease that does not usually lead to death. It is confirmed that the Prophet said: "O Slaves of Allaah! Seek treatment. Indeed Allaah has not sent down any illness without sending a cure for it except one disease which is the decrepitude." [Abu Daawood]

We conclude from this Hadeeth that it is permissible [and not obligatory] to seek treatment.

Therefore, it is permissible not to seek treatment if the patient can endure the pain and will not despair of Allaah's Mercy. However, if the patient fears that he cannot be patient and pleased with what Allaah has decreed for him, then it is better for him to seek treatment especially if it is expected that when he becomes healthy he will benefit the people, and the disease could prevent him from doing so. The same thing applies if it is expected that when he is in a healthy condition he will perform more good deeds and acts of obedience to Allaah.

However, if it is sure that the disease is fatal, then the patient is obliged to seek treatment as Allaah forbade us from killing a soul. Allaah Says (what means): {And do not kill yourselves (nor kill one another). Surely, Allaah is Most Merciful to you.} [Quran 4:29].

Allaah has also forbidden us from causing destruction of our own selves as He Says (what means): {...and do not throw yourselves into destruction.}[Quran 2:195]

Allaah Knows best.