Khella is available in the form of tinctures, tablets, and prescription creams (for vitiligo). In the form of oil (omam) it is almost colorless (slightly brownish) with characteristic odour and a sharp hot taste. Another form of it – Omam water - water distilled from the seeds (which is extremely popular in some Arabian countries, south India, Malaysia and Srilanka. Khella also is an ingredient in many products and herbal remedies.
==Special Precautions of Khella==
* Be careful not to confuse khella with its less commonly used relative, [[Bishop's Weed]]. The two species contain some of the same chemicals and work similarly in the body, but khella is more commonly used for heart and lung conditions, and bishop's weed is more commonly used for skin conditions.
* Khella is POSSIBLY UNSAFE when taken in high doses or used for a long time. It can cause side effects including liver problems, nausea, dizziness, constipation, lack of appetite, headache, itching, trouble sleeping, and skin sensitivity to sunlight (photosensitization).
*Too much exposure to sunlight while using khella can cause skin hypersensitivity to sunlight.
* Medications that can harm the liver (Hepatotoxic drugs) interacts with KHELLA
* Medications that increase sensitivity to sunlight (Photosensitizing drugs) interacts with KHELLA
==The benefits and uses of Khella are==
Bishop’s Weed contains thymol (35 to 60%), which has antibacterial, anti-fungal, and preservative properties. Khella’ herbal properties conclude also antispasmodic, smooth muscle relaxing action. It is a non-stimulating bronchial dilator and vasodilator. Its other important constituents are: the essential oil (2.5 to 5% in the dried fruits), isothymol (50%), α-pinene, p-cymene, γ-terpinene and limonene. In fruits there are also coumarins and furocoumarins (psoralens), the most important of which are khellin (1%) and visnagin (0.3%), and a small amount (less than 0.03%) of a volatile oil.