Bukhari

Hadith Commentary:
Regarding honey, Allah Himself has stated: ﴿فِیهِ شِفاء لِلناسِ﴾ (an-Nahl: 69)
That is, in honey there is healing for people, because it is the precious extract of most plants, which the honeybee gathers by sucking the nectar of the flowers of plants.
In this narration, the patient who is mentioned—after being given honey repeatedly, his diarrhea stopped on its own.
When all the harmful matter in the stomach was expelled, the honey then had its complete effect on the person.
That is, it stopped his diarrhea. This is, in fact, the fundamental principle and the basis of homeopathic treatment.

Hadith Commentary:
(1)
Regarding honey, Allah the Exalted has stated that there is healing for people in it, because it is the extract of many plants which the honeybee gathers by sucking the nectar of flowers.
(2)
In this narration, the patient who is mentioned was given honey several times, and finally, upon giving honey, the diarrhea stopped on its own.
When the harmful substance in the stomach was expelled, the honey then had its complete effect.
Hafiz Ibn Hajar rahimahullah writes that the honey did not benefit upon the first drinking because the quantity and quality required for the illness were less than needed, thus full recovery did not occur.
If the quantity had been increased, there was a risk of other illnesses; therefore, by giving it repeatedly, when the required amount for the illness was fulfilled, by Allah’s command the patient became healthy.
(Fath al-Bari: 10/209)

Hadith Commentary:
In this case, its harmful substances were expelled and he became healthy.
Among the countless benefits of honey is that it cleanses the stomach and corrects digestion, which is fundamental for health.
Maulana Waheeduz-Zaman states that this hadith is the foundational principle of homeopathic medicine, in which treatment is always done by similars (treatment by like).
That is, for example, if someone is experiencing diarrhea, then a purgative medicine is given.
Similarly, if someone has a fever, then a medicine is given that produces fever. Such a medicine, through its action, initially increases the illness in the patient, but ultimately, it acts in accordance with the patient. Allah Ta’ala has placed a wondrous effect in medicines.
Castor oil, in the same way as honey, is a purgative (mus-hil), but when someone is experiencing diarrhea, these very medicines, in the end, cause constipation. In Unani and allopathic medicine, treatment is done by opposites, etc. (Waheedi)

Hadith Commentary:
(1)
In one narration, it is explicitly mentioned that the patient was suffering from diarrhea due to an upset stomach, so the Messenger of Allah (sallallahu alayhi wa sallam) prescribed honey for him.
(Sahih Muslim, Kitab al-Salam, Hadith: 5770 (2217))

(2)
Some atheists have objected to this hadith, saying that honey itself causes diarrhea, so how can it cure someone who already has diarrhea? But this objection is based on their ignorance, because there are two methods of treatment:
One is to give medicine that is similar to the illness; this is called treatment by similarity (ilaj bil-muwafiq):
For example:
If someone has a fever, he is given medicine that induces fever.
This type of medicine initially increases the illness, but then recovery occurs.
This is the principle in homeopathic medicines.
The second method is to give medicine that is the opposite of the illness, which eliminates the germs of the disease.
This is called treatment by opposition (ilaj bil-didd).
This is the principle in Unani medicine.
The Messenger of Allah (sallallahu alayhi wa sallam) prescribed honey for the patient according to the first method of treatment, so that the harmful matter would be expelled thoroughly. And this is exactly what happened: after the harmful matter was expelled, the patient became healthy.
And Allah knows best.

(3)
In any case, Imam al-Bukhari (rahimahullah) has established from this hadith that treating with honey is permissible in the Shari‘ah, whether pure honey is given or it is used mixed with something else.

Hadith Commentary:
Vocabulary of the Hadith:
(1)
Istalaqa batnuhu:
He suffered from diarrhea or loose motions.

(2)
Sadaq Allah:
Allah’s statement,
﴿fihi shifa﴾ “In it is healing,”
is correct,
your brother’s stomach will certainly be cured.

(3)
Kathaba batnuhu:
His stomach is lying,
this treatment is working for him,
but all the harmful substances have not yet been expelled.

Benefits and Issues:
Dr. Khalid Ghaznavi has written,
The cause of diarrhea is inflammation in the intestines,
which can be due to bacteria, their toxins, or viruses.
If the movements of the intestines in such a patient are stopped immediately, the inflammation will persist,
or the toxins will remain there.
Therefore, the best method of treatment is to first cleanse the intestines,
then kill the bacteria.
Honey had the ability to do both these things,
(Tibb Nabawi sallallahu alayhi wa sallam and Modern Science, p. 171).

Since this man suffered from diarrhea due to indigestion and infection (bad odor) in the intestines,
diarrhea was beneficial for him.
Therefore, by repeatedly giving him honey, his stomach was cleansed,
and when the stomach was completely cleansed of the filthy material, he became healthy.