Sahih Bukhari

Narrated Anas:The climate of Medina did not suit some people, so the Prophet ordered them to follow his shepherd, i.e. his camels, and drink their milk and urine (as a medicine). So they followed the shepherd that is the camels and drank their milk and urine till their bodies became healthy. Then they killed the shepherd and drove away the camels. When the news reached the Prophet he sent some people in their pursuit. When they were brought, he cut their hands and feet and their eyes were branded with heated pieces of iron. Sahih Al-Bukhari, Vol. 7, Bk. 71, No. 590. (Also, see No. 589.)

Narrated Anas: Some people from the tribe of 'Ukl came to the Prophet and embraced Islam. The climate of Medina did not suit them, so the Prophet ordered them to go to the (herd of milch) camels of charity and to drink, their milk and urine (as a medicine). They did so, and after they had recovered from their ailment (became healthy) they turned renegades (reverted from Islam) and killed the shepherd of the camels and took the camels away. The Prophet sent (some people) in their pursuit and so they were (caught and) brought, and the Prophets ordered that their hands and legs should be cut off and that their eyes should be branded with heated pieces of iron, and that their cut hands and legs should not be cauterized, till they die. Sahih Al-Bukhari Vol. 8, Bk. 82, No. 794. 

Sahih Muslim

Anas reported: Eight men of the tribe of 'Ukl came to Allah's Messenger (may peace be upon him) and swore allegiance to him on Islam, but found the climate of that land uncogenial to their health and thus they became sick, and they made complaint of that to Allah's Messenger (may peace be upon him), and he said: Why don't you go to (the fold) of our camels along with our shepherd, and make use of their milk and urine. They said: Yes. They set out and drank their (camels') milk and urine and regained their health. They killed the shepherd and drove away the camels. This (news) reached Allah's Messenger (may peace be upon him) and he sent them on their track and they were caught and brought to him (the Holy Prophet). He commanded about them, and (thus) their hands and feet were cut off and their eyes were gouged and then they were thrown in the sun, until they died.

This hadith has been narrated on the authority of Ibn al-Sabbah with a slight variation of words. Sahih Muslim, Book 16, Number 4131 (Also, see 4130, 4132).

Of course, many Muslims find the idea of drinking camel's urine to be repulsive; and, as a result, they reject this hadith, even though it is Muttafaq 'Alaih. Others justify the hadith, and point out that horse urine is the source of conjugated equine estrogens (CEE) and available as Premarin®.  It is an estrogen treatment for menopausal and premenopausal women.  For them, it is reason to praise Muhammad whom, they claim, had miraculous foreknowledge of modern medicine.  However, there is no specific evidence that those who were ill were menopausal women or that Muhammad suggested that camel urine would cure a woman who had a low level of estrogen.

Furthermore, those Muslims who think that Muhammad was given miraculous scientific knowledge only give lip service to this hadith.  They would never put camel urine to their lips and drink it themselves.  This shows that they don't really believe the so-called miracle in their hearts.  If they did, they would be asking to drink camel's urine whenever they were ill. Since they neither believe nor follow Muhammad's advice in this hadith, their verbal praise of Muhammad's miraculous medical knowledge rings hollow and hypocritical.

Even more striking than the advice to drink camel's milk and urine is the horrific mutilation of the murderers.  Since Muhammad commanded that their eyes be branded with a hot iron, and since their hand and feet were cut, tradition records that someone said, "I saw one of them licking the earth with his tongue till he died." When Muhammad commanded them to be mutilated, he did not allow the cuts on their hands and feet to be cauterized.  He wanted them to die the most slow, painful, dry, and agonizing death possible. (See Sahih Al-Bukhari No. 589 of Vol 7.)  

Yet, the Qur'an claims Muhammad's mission was only a mission of mercy for peoples.  

And We have sent you (O Muhammad SAW) not but as a mercy for the 'Alamin (mankind, jinns and all that exists). 21:107 [Al-Hilali & Khan's translation]