The best days for cupping (Hijama) are the 17th, 19th, and 21st of the Islamic month which coincides with Monday, Tuesday, or Thursday.

Anas ibn Maalik (may Allaah be pleased with him) reported that the Messenger (Sallallaahu Álayhi Wasallam) said, “Whoever  wants to perform cupping (Hijama) then let him search for 17th, 19th, and 21st…” [Saheeh Sunan ibn Maajah (3486)].

Ibn Umar (may Allaah be pleased with him) reported that the Messenger (Sallallaahu Álayhi Wasallam) said, “Cupping (hijama) on an empty stomach* is best. It is a curse and a blessing. It improves intellect and memory. So cup yourselves with the blessing of Allaah on Thursday. Keep away from cupping (hijama) on Wednesday, Friday, Saturday, and Sunday to be safe. Perform cupping (hijama) on Monday and Tuesday for it is the day that Allaah saved Ayoub from a trial. He was inflicted with the trial on Wednesday. You will not find leprosy except (by being cupped) on Wednesday or Wednesday night.” [Saheeh Sunan ibn Maajah (3487)].

Ibn Umar (may Allaah be pleased with him) reported that the Messenger (Sallallaahu Álayhi Wasallam) said,

“Cupping (Hijama) on an empty stomach* is best. It increases intellect and improves memory. It improves the memory of the one memorizing. So whoever is going to be cupped then (let it be) on a Thursday in the name of Allaah.  Keep away from being cupped on a Friday, Saturday, and Sunday. Be cupped on a Monday or Tuesday.

Do not be cupped on a Wednesday because it is the day that Ayoub was befallen with a trial. You will not find leprosy except (by being cupped) on Wednesday or Wednesday night.” [Saheeh Sunan ibn Maajah (3488)].

* ‘alaa ar-reeq in arabic means to fast until after being treated with cupping. Once the treatment of cupping has been completed, one may eat and drink. 

As for the Islamic day and night, the night enters before the day. So at sunset on Tuesday, Wednesday night comes in. Cupping (Hijama) is best performed during the daytime between the adhaan of fajr and the adhaan of maghrib because yawm in arabic means daytime.

The Sunnah days for cupping (Hijama) every month are when the 17th or 19th or 21st of the lunar month coincide with a Monday, Tuesday, or Thursday. These are the best and most beneficial days for cupping (Hijama). If one is not able to be cupped on the 17th, 19th 21st(coinciding with Monday, Tuesday, or Thursday) then any Monday, Tuesday, or Thursday month.