Nigella sativa has been used for a long time in Jordanian folk medicine to treat skin diseases like microbial infections and inflammation. Therefore, the present study was conducted to assess the healing efficacy of petroleum ether extract of nigella sativa seeds (fixed oil) on staphylococcal-infected skin. Male BALB/c mice were infected with 100 microL of Staphylococcus aureus (ATCC 6538) suspension at a dose of 10(8) colony forming unit/mouse into shaved mild dorsal skin. Application of treatments for each group (100 microL sterile saline, 100 microL chloramphenicol (10 microg/mouse) and nigella sativa fixed oil at a dose of 50, 100 or 150 microL/mouse) was performed at the site of infection twice a day for two consecutive days after 3 h of infection. At day 3 and 5 after infection, total White blood Cells (WBCs) count; differential and absolute differential WBC counts and the number of viable bacteria present in the skin area were measured. At day 5 after infection, the animals were sacrificed and the histology of skin was examined. Results indicated that fixed oil of nigella sativa seeds enhance healing of staphylococcal-infected skin by reducing total and absolute differential WBC counts, local infection and inflammation, bacterial expansion and tissue impairment. These effects provide scientific basis for the use of nigella sativa in traditional medicine to treat skin infections and inflammations.