It is mentioned in a Hadith that hijama (cupping) can be done at night.

Answer

On any subject or act there are generally conflicting views to be found in the Hadith. The Ahaadith have been interpreted differently by authorities. If one authority says that in terms of the Hadith hijaamah should not be at night, and another one says that it can be done, then intelligence demands that the precaution is in abstention. If done during the night, it may be harmful in terms of the one interpretation. But if done during the day, according to all authorities, there is no harm. Now, you can make your own choice. We are not saying that it is not permissible to do hijaamah at night. We are not aware. We have not sufficiently researched this issue.