Umm Salamah (may Allah be pleased with her) narrated, "The woman who has just delivered would remain for forty days afterwards [without praying or fasting]. One of us would then overlay Warss on her face to help against spots." Abu Hanifah, a linguist, said, "Warss does not grow in the wild. Rather, it is cultivated. I think that it is only grown in the Arab lands, especially in Yemen."
Warss is dry and hot in the second degree. The best type of Warss is the red Warss, which is soft in the hand and does not have much bran. Warss is used as an ointment to treat spots, rashes, and pimples that appear on the surface of the skin. Warss constipates, has a dyeing quality and helps against leprosy when taken as a drink.
Warss has similar benefits to sea Qust, and if it is used as an ointment it relieves vitiligo (skin condition of unkown cause, characterized by patchy loss of pigment), rashes, pimples and ulcers.
Taken From: Healing With The Medicine Of The Prophet (peace be upon him), By Imam Ibn Qayyim Al-Jauziyah