Shama-il Tirmidhi Chapter 049, Hadith Number 001 (343).

Anas Radiyallahu'Anhu was asked regarding the payment to a hajjaam (cupper). (Is it permissible or not?) Anas Radiyallahu 'Anhu replied: "Rasulullah Sallallahu 'Alayhi Wasallam took the treatment of cupping which was administered by Abu Taybah Radiyallahu 'Anhu, he was given two saa' food (in a narration it is mentioned that dates were given), and Sayyidina Rasulullah Sallallahu'Alayhi Wasallam interceded on his behalf to his master that the stipulated amount he was responsible for be made less. He also said this, that cupping is the best of medicine".

Commentary
When Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam himself paid the price, then the answer to the question is apparent. It is possible that the aim of the question was this, that in a few ahaadith this occupation has been scorned. The reason being, that blood has to be sucked out which is an unclean thing, therefore, it is essential that one be careful, and care be taken that the mouth be kept paak at all times. In the same manner, the same has been said in the ahaadith regarding some other occupations. As a result it created doubt and perplexities in the minds of some people, whereas, the meaning of the narrations is simple and clear. Whatever Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam said regarding an occupation there was something in it that one had to be careful about, and which needed to be remedied. In the above hadith, by 'income' is meant, that a slave is given the opportunity, that if he agrees to pay daily a certain amount, he is given a limited freedom. The extra that he earns belongs to him. This type of slave is called 'Abd Ma'dhu,. It was originally stipulated that this slave pay three saa' daily. By the intercession of Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam one was made less after which there remained only two 2 saa' to be paid daily. There is a difference of opinion among the 'ulama regarding the weight of the saa'. According to the Hanafi jurists a saa' equals approximately four seers (approx. 3,8kg). The saying of Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam that cupping is the best medicine is very true. By this he was addressing the youth of the Haramayn, and also the inhabitants of the countries where the climate is hot, because their blood becomes thin, it remains more on the surface of the body and the climate of the country brings it even more closer to the surface.

Therefore the 'ulama say it is not advisable for those above the age of forty to take the treatment of cupping.