It is argued that the following Hadith ignores reality and asks to blindly believe in God even when it apparently contradicts reality.
Narrated Abu Said: A man came to the prophet and said, 'My brother has got loose motions. The Prophet said, Let him drink honey." The man again (came) and said, 'I made him drink (honey) but that made him worse.' The Prophet said, 'Allah has said the Truth, and the abdomen of your brother has told a lie."[1]
Other version has the following addition towards the end.
"Let him drink honey." So he made him drink honey and he was cured.[2]
Mufti Taqi Usmani explaining the phrase in question writes:
"The people of Hijaz use the word "kizb" to mean mistake/error. This is as al-Khattabi has pointed out that they say, "Your hearing has lied" i.e. he has erred and has not understood what was said to him. And in the saying of the Prophet (peace be upon him):
"The stomach of your brother has lied" is an indication that this medicine (in the form of honey) is beneficial for him.
The persistence of disease is not for the ineffectiveness of the medicine rather for the problem with the stomach of your brother that it has a lot of infectious matter and the quantity of the medicine benefits when it according to severity of the disease.
If the disease is severe the use of the medicine for a short duration does not benefit and it requires repetitive and consistent intake.
For this reason the Messenger of Allah (peace be upon him) ordered him to drink honey again."[3]
Indeed, Allah knows the best.
Footnotes:
[1] Sahih Bukhari, book 71, Hadith no. 614
[2] Sahih Bukhari, book 71, Hadith no. 588
[3] Takmila Fath al-Mulhim, vol. 4, p. 313