The black seed (Nigella sativa), a member of the Runuculaccae family, is an annual plant growing in countries bordering the Mediterranean sea (Jansen, 1981). It is one of the native plants that arc widely distributed in Egypt (Hashem and EI·
Kiey, 1982). In Arabian folk medicine, the black seed and its constituents, especially oils, have been used for treatment of many diseases such as diabetes. hypertension, bronchial asthma and rheumatism (Hashem and El-Kiey, 1982). Moreover. Nigclla sativa seeds are digestive stimulants as well as carminative. diuretic, ami-hclmintic.
antitumor activity (Hassan and EI-Dakhakhny, 1992). an immune modulating effect (El-Kadi et al., 1987) and cytoprotectivc effect on tissues exposed to cytotoxic agents (El-Kadl et at, 1987). It is reponed that the seeds contain fixed and volatile oils which contain thyrnoquinone (El-Dakhakhny, 1995). It has been reported that thymoquinone protects organs sgainst oxidative damage induced by a variety of free radical generating agents (EI-Tahir et at, 1993). It was reported also that thyrnoquinone has an anri-Inflammatory activity in rats and inhibits eicosanoids generation in
leukocytes (Ligumsky et al., 1995) and non enzymatic peroxid.nion in brain phospholipid liposornes (Kolbasa et al., 1998). Thymoquinone reduces free radical generation especially hydroxyl radicals. These hydroxyl radicals arc known to playa
major role in the pathogenesis of gastric mucosal ulcer (Kolbasa et at, 1998).
Indomethacin is widely used in treating many diseases as rheumatic diseases, gout and fevers. Many roxie and side effects can be seen due to the use or abuse of indomethacin, especially those related to the gastroimestinal tract due to its local  irritant effect, that leads to gastric erosion and ulceration (Houghton et al., 1995). It is clear that Nigella sativa has a very low toxicity on oral administration (Zaoui et al., 2002). so the present work was done to study the ability of Nigella sativa oil as a cytoprotective agent against oxidative gastric mucosal damage induced by local irritanteffect of indomethacin in albino rats, Also, the study of the histological effect of indomethacin on gastric mucosa and effect of Nigella sativa oil on gastric mucosal lesion induced by indomethacin were studied.