The Quran and medicine
Question

I heard in a lecture that medical scientists or doctors claim that many medicines&treatements have been discovererd&propounded by inferring facts frm the Holy Quran.  
Now my question is, Is that all regarding medicine is mentioned in the Holy Quran? Or is there more left which we've to still put into use? 
I'm asking this question with regards to an earnest request frm a friend of mine, a hindu named Vignesh and he asked me whether there r matters left still in the Holy Quran to control some of these deadly diseases.
Praise be to Allah.Firstly: 
Allah sent Muhammad (peace and blessings of Allah be upon him) with a religion that covers all aspects of life, as Abu Dharr (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) left us and no bird flapped its wings in the sky except that he had taught us some knowledge about it. 
(Narrated by Ahmad, 20399. See Majma’ al-Zawaa’id, 8/263. al-Haythami said: it was narrated by al-Tabaraani and its men are the men of saheeh apart from Muhammad ibn ‘Abd-Allah ibn Yazeed al-Muqri’ who is thiqah (trustworthy)). 
Islam came to meet the needs of people in all aspects of their lives.  
Secondly: 
What is narrated in the Sunnah from the Prophet (peace and blessings of Allah be upon him) complements what is in the Quran. These two sources are the principal sources for Muslims. The Prophet (peace and blessings of Allah be upon him) has told us that Allah has not sent down any disease but He has also sent down a cure for it. 
It was narrated from Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “Allah has not sent down any disease but He has also sent down a cure for it.” 
Narrated by al-Bukhaari, 5678. 
Thirdly: 
What the questioner has mentioned, that some Muslims say that many remedies were discovered through the Holy Quran, we say that this is somewhat exaggerated. 
The Quran is not a book of medicine or geography or geology as some Muslims like to say to westerners. Rather it is a book of guidance for mankind and one of the greatest of its miracles is its eloquence and the ideas and concepts that it contains. This is the main aspect of its miraculous nature. Allah revealed it to His Prophet (peace and blessings of Allah be upon him) at a time when eloquence had reached great heights, so this book came to amaze those people and challenge them in their area of expertise, to prove to them that it was from Allah. 
This is not strange, and it is nothing new in religion. The signs of Moosa (peace be upon him) – his stick and his hand – were of the kind that was prevalent during his time, which was magic (sihr). The signs of ‘Eesa (peace be upon him) – raising the dead and healing the blind and lepers – were of the kind that his people were skilled in and that was widespread among them, which was medicine. 
Hence we say that the greatest feature of the Quran is its eloquence. Scholars nowadays are still discovering new aspects of its eloquence through their study of its verses.  
This does not mean that there is no other miraculous aspects to the Quran. Rather in some verses Allah mentions things about the design of the human body, the stages of its creation and development, some natural phenomena, etc. 
But with regard to cures for various diseases, as the questioner mentions, the Quran is a healing for the believers. This includes healing the heart (mental or spiritual disease) and physical healing. Allah mentions honey in the Quran and says that it is a healing for mankind. And He mentions the principle of preserving good health and guarding against sickness. So whoever says that the Quran says a lot about medicine in this regard is right, but whoever goes beyond that is exaggerating. Rather this is a kind of exaggeration coined by some Muslims. The Quran is not a book of medicine. There are some diseases that did not exist previously, so how could their cure come – according to what the questioner says – before they appeared? 
Fourthly: 
(a)The following are some of the verses which indicate that the Quran is healing:
Allah says (interpretation of the meaning): 
“And We send down of the Quran that which is a healing and a mercy to those who believe”
[al-Isra’ 17:82]
Ibn al-Qayyim (may Allah have mercy on him) said: 
Allah says “And We send down of the Quran that which is a healing and a mercy to those who believe”. The correct view is that the word min (translated here as “of”) serves to explain the nature of the Quran as a whole, not to refer to parts of it and not other parts.  
Allah says (interpretation of the meaning): 
“O mankind! There has come to you a good advice from your Lord (i.e. the Quran, enjoining all that is good and forbidding all that is evil), and a healing for that which is in your hearts”
[Yoonus 10:57]
The Quran is the complete healing for all mental, spiritual and physical diseases, all diseases of this world and the Hereafter. But not everyone is guided to use it for the purpose of healing. If the sick person uses the Quran for healing in the proper way, and applies it to his disease with sincerity, faith, complete acceptance and firm conviction, fulfilling all its conditions, then no disease can resist it. 
How can disease resist the words of the Lord of heaven and earth which, if He had revealed it to the mountains they would have crumbled and if He had revealed it to the earth it would have broken it apart? There is no sickness, spiritual or physical, but in the Quran there is that which indicates its remedy, its cause and how to protect against it for those who are blessed with understanding of His Book. 
Zaad al-Ma’aad, 4/352 
(b)The Quran contains the treatment for hearts and souls, and as such it is a means of expelling all sicknesses from the body. In this regard the Quran is a healing and a remedy for many diseases.
Ibn al-Qayyim (may Allah have mercy on him) said: 
We and others have tried this on many occasions and we have seen that it works in ways that physical remedies do not. Indeed we now regard physical medicine as the doctors regard folk medicine. This is in accordance with the law of divine wisdom, not contrary to it, but the causes of healing are many and varied. When the heart is in contact with the Lord of the Worlds, the Creator of the disease and the remedy, the Controller of nature Who directs it as He wills, he has other remedies apart from the remedies that are sought by the heart that is far away from Him and that turns away from Him. It is known that when a person’s spirits are high and his body is in good shape, they cooperate in warding off disease and suppressing it, so if a person is in high spirits and physical good shape, finds comfort in being close to his Creator, loving Him, enjoying remembrance of Him (dhikr), devoting all his strength and power for His sake and focusing on Him, seeking His help, putting his trust in Him, how can anyone deny that this is the greatest medicine or that this spiritual power gives him the means to ward off pain and defeat it completely? No one would deny this but the most ignorant of people, those who are furthest away from Allah and the most hard-hearted and unaware of human nature. 
Zaad al-Ma’aad 4/12 
(c)In the Quran there is Soorat al-Faatihah which is a ruqyah to be recited as a prayer for healing.
It was narrated that Abu Sa’eed (may Allah be pleased with him) said: “A group of the companions of the Prophet (peace and blessings of Allah be upon him) set out on a journey and traveled until they stopped in (the land of) one of the Arab tribes. They asked them for hospitality but they refused to welcome them. The chief of that tribe was stung by a scorpion and they tried everything but nothing helped them. Some of them said, ‘Why don’t you go to those people who are camped (near us), maybe you will find something with them.’ So they went to them and said, ‘O people, our chief has been stung by a scorpion and we have tried everything but nothing helped him. Can any of you do anything?’ One of them said, ‘Yes, by Allah, I will recite ruqyah for him, but by Allah we asked you for hospitality and you did not welcome us, so I will not recite ruqyah for you until you give us something in return.’ Then they agreed upon a flock of sheep.’ Then he went and spat drily and recited over him Al-hamdu Lillaahi Rabb il-‘Aalameen [Soorat al-Faatihah]. (The chief) got up as if he was released from a chain and started walking, and there were no signs of sickness on him. They paid them what they agreed to pay. Some of them (i.e. the companions) then suggested to divide their earnings among themselves, but the one who performed the ruqyah said, ‘Do not divide them until we go to the Prophet (peace and blessings of Allah be upon him) and tell him what happened, then wait and see what he tells us to do.’ So they went to the Messenger of Allah (peace and blessings of Allah be upon him) and told him what had happened. The Messenger of Allah (peace and blessings of Allah be upon him) asked, ‘How did you know that it (al-Faatihah) is a ruqyah?’ Then he added, ‘You have done the right thing. Share out (the flock of sheep) and give me a share too.’ And the Messenger of Allah (peace and blessings of Allah be upon him) smiled.”   
Narrated by al-Bukhaari, 2156; Muslim, 2201 
Ibn al-Qayyim said concerning Soorat al-Faatihah:  
Whoever is guided by Allah and is given good insight to understand the deep meaning of this soorah and what it contains of Tawheed, understanding of the Divine nature, the names, attributes and actions of Allah, the Divine decree, the Resurrection, rejecting any misconception that undermines the concept of the Oneness of the Divine Lordship and Divine nature, complete trust in Allah and referring all one’s affairs to the One Who has full control of all things – to Him be all praise, for all goodness is in His hand and to Him all things return – and feeling in need of Him in seeking guidance that is the root of happiness in this world and in the Hereafter, will realize the connection between the contents of this soorah and bringing good and warding off evil. He will understand that ultimate goodness and blessing is connected to this soorah and is dependent upon understanding it and acting upon it. Then this soorah will make him independent of many other kinds of medicine and ruqyah, and it will open the door to a great deal of goodness and ward off a great deal of evil. 
Zaad al-Ma’aad, 4/347 
(d)The Quran mentions the principle of maintaining good health.
Ibn al-Qayyim said: 
The basic principles of medicine are three: prevention, maintaining good health, and removing harmful substances from the body. 
Allah has mentioned them all together, to His Prophet and his ummah in three places in His Book. 
He prevented the sick person from using water lest it harm him, as He says (interpretation of the meaning): 
“And if you are ill, or on a journey, or one of you comes after answering the call of nature, or you have been in contact with women (by sexual relations) and you find no water, perform Tayammum with clean earth and rub therewith your faces and hands (Tayammum)”
[al-Nisa’ 4:43]
Allah allowed the sick person to do tayammum to protect him, just as He permitted it to the one who has no water. 
Allah says concerning the maintenance of good health: 
“and whoever is ill or on a journey, the same number [of days which one did not observe Sawm (fasts) must be made up] from other days”
[al-Baqarah 2:185]
The traveller is allowed to break his fast during Ramadaan, to protect his health lest the combination of fasting and the difficulties of travel weakens him and affects his health. 
And Allah said concerning the removal of harmful things by shaving the head of the person in ihraam (for Hajj or ‘Umrah): 
“And whosoever of you is ill or has an ailment in his scalp (necessitating shaving), he must pay a Fidyah (ransom) of either observing Sawm (fasts) (three days) or giving Sadaqah (charity — feeding six poor persons) or offering sacrifice (one sheep)”
[al-Baqarah 2:196]
So if a person has an ailment in his scalp when he is in ihraam, he is permitted to shave his head and remove the harmful thing or the bad substance that is causing lice to develop – as happened to Ka’b ibn ‘Ajrah – or if it is causing sickness to develop. 
These three matters are the basic principles of medicine. We have mentioned an example of each one in order to point out the blessing of Allah to His slaves in preventing sickness, protecting their health and removing harmful substances from them, as a mercy and kindness towards His slaves, for He is the Most Kind, Most Merciful. 
Zaad al-Ma’aad, 1/164, 165 
Ibn al-Qayyim said: On one occasion I discussed this with one of the chief doctors of Egypt, and he said: By Allah if I had to travel to the west to obtain these benefits that would not be too much – or words to that effect. 
Ighaathat al-Lahfaan, 1/25 
(e)Mention of honey in the Quran, and that it is a healing for mankind.
 Allah says (interpretation of the meaning): 
“There comes forth from their [bees’] bellies, a drink of varying colour wherein is healing for men”
[al-Nahl 16:69]
Ibn al-Qayyim (may Allah have mercy on him) said: 
With regard to the Prophet’s guidance concerning drinking, it is the most perfect guidance that maintains good health. He used to drink honey mixed with cold water. This is very healthy and no one can understand how healthy it is except the most prominent doctors. For drinking honey on an empty stomach dissolves phlegm, cleanses the stomach, reduces its viscosity, washes away waste matter, warms it up a little and opens its inlet and exit. It has a similar effect on the liver, kidneys and urethra. It is more beneficial to the stomach than any other kind of sweet that enters it. However it may cause side effects in people who are suffering from jaundice because it is hot and jaundice is hot, so it may aggravate it; in order to avoid this effect vinegar may be added, then honey will become beneficial and drinking it will be more useful than many or most of the drinks that are made from sugar, especially for those who are not used to these drinks, for if they drink them they will not suit them as well as honey does, or even come close.  
With regard to drinking it when it is collected and well-prepared, this is one of the most beneficial things for the body, and one of the greatest means of preserving health; it is very refreshing and energizing, and it is good for the liver and heart. If it is well-prepared it provides nutrition and makes food reach all parts of the body in the most effective manner. 
Zaad al-Ma’aad, 4/224, 225 
And he said (may Allah have mercy on him): 
Honey contains great benefits, for it cleanses impurities from the veins and stomach etc, whether it is eaten or applied to the skin. It is good for the elderly, the phlegmatic and those whose humours are cold and wet. It is nourishing, aids digestion, energizes, makes unpleasant medicine palatable, is good for the liver and chest, is a diuretic and helps to ease coughs caused by phlegm. If it is drunk warm mixed with rosewater it is beneficial for one who has been bitten by a scorpion or who has consumed opium. If it is drunk on its own mixed with water, it is good for the one who has been bitten by a rabid dog or eaten poisonous mushrooms. If fresh meat is placed in honey, it will stay fresh for three months, as will cucumbers, pumpkins and eggplants. Many fruits can be kept in it for six months. It will also preserve a dead body, and it is known as the trustworthy preserver. If the body of one who is afflicted with lice is painted with honey, it will kill the lice and their eggs. It makes the hair long, beautiful and smooth. If used on the eyes like kohl it clears the vision. If the teeth are brushed with it, it whitens the teeth and makes them bright, and keeps the gums healthy. It opens the veins and induces menstruation. If taken on an empty stomach it takes away phlegm and cleanses the stomach, clearing away waste matter and restoring the correct temperature. It does likewise to the liver, kidneys and urethra.
 As well as all this, it has no side effects and causes little harm. It may cause side effects in one who is suffering from jaundice, but that may be counteracted by vinegar and the like, in which case it becomes very beneficial for him.
 It is a kind of nourishment, a kind of medicine, a kind of drink, a kind of sweet, a kind of cream. There is nothing that has been created for us for a similar purpose that is better than it, or even comes close. The ancient peoples relied on it, and in most of the books of the ancients there is no mention of sugar at all and it was unknown to them, for it is something that is very new. The Prophet (peace and blessings of Allah be upon him) used to drink honey mixed with water on an empty stomach, and this is the secret of maintaining good health that no one can understand except one who is intelligent and blessed.
Zaad al-Ma’aad, 4/33, 34.