Black seeds are supposed to be good for the respiratory system, in particular nigella sativa, the seeds mentioned (in a hadith?) by the Prophet. These came from the Yemenis’ store, so I’m sure they’re authentic.
Google tells me I can make a tea by pouring boiling water over a tablespoon of the seeds, covering the cup while it steeps, and adding honey. This is the same method I learned in Jordan when one of my students made me a cup of zaatar (fresh thyme leaves, not the dried “zait and zatter” type) for a cold. The taste seemed a bit weak, so this morning I decided to try a seed method I learned in Amman using anise seeds for bronchitis. The herb is boiled in a small espresso pan for several minutes and poured into the glass though a tea strainer. Here it is in an everyday casset shai (tea glass).
Biblical and Koranic mentions from wiki:
Caraway is not threshed with a sledge,
nor is a cartwheel rolled over cumin;
caraway is beaten out with a rod,
and cumin with a stick.
[Sahih Muslim : Book 26 Kitab As-Salam, Number 5489]
Abu Huraira (Radi Allah Anhu) reported that he heard Allah’s Messenger as saying: Nigella seed is a remedy for every disease except death.
Narrated Khalid bin Sa’d :We went out and Ghalib bin Abjar R.A was accompanying us. He fell ill on the way and when we arrived at Medina he was still sick. Ibn Abi ‘Atiq came to visit him and said to us, “Treat him with black cumin. Take five or seven seeds and crush them (mix the powder with oil) and drop the resulting mixture into both nostrils, for ‘Aisha has narrated to me that she heard the Prophet (sallalhu-alaihewasallam) saying, ‘This black cumin is healing for all diseases except As-Sam.’ ‘Aisha said, ‘What is As-Sam?’ He said, ‘Death.’ ” (Bukhari)
Avicenna, most famous for his volumes called The Canon of Medicine, refers to nigella as the seed that stimulates the body’s energy and helps recovery from fatigue and dispiritedness. It is also included in the list of natural drugs of ‘Tibb-e-Nabavi’, or “Medicine of the Prophet”, according to the tradition “hold onto* the use of the black seeds for in it is healing for all diseases except death” (Sahih Bukhari vol. 7 book 71 # 592).
*hold onto indicates long term use; studies have reported changes in blood chemistry after several weeks