Background: Head lice infestation caused by Pediculus humanus var. Capitis, is the most prevalent human ectoparasitic disease worldwide, head lice are haematophagous, head lice infestation is particularly frequent among children 3-11 stigmatization and psychological distress. Traditional pharmacological therapies for the human head louse, Pediculus humanus Capitis, have focused on 1 or 2 courses of various ovicidal and pediculicidal topical therapies, permetherin 1% as first-line treatment for head lice, permetherin is abroad- spectrum synthetic pyrethroid, and trimethoprim /sulfamethoxazole is presumed to work by ridding lice of bacteria. Methods and Patients: Seventy five females patients with pediculosis capitis included in the study, their ages ranged from 3 to 60 years. In 40 patients the pediculosis was complicated by secondary bacterial infection. The patients were divided in to three groups, each group consisted of twenty five patients. Group 1:-The patients were treated by 5% permetherin solution applied for three successive days for 30 minutes for each application and repeated after 10 days as a single application for 30 minutes. Group 2:-Was treated by trimethoprim /sulfamethoxazole tablet or solution according to the age for 5 days. Group 3:- Was treated by combination of 5% permetherin solution and oral trimethoprim /sulfamethoxazole in similar does to the first and second groups. Swabs were taken from patients with bacterial infection. Results: The study revealed that 23(92%) patients of the first group who was treated by 5% permetherin solution, was cleared, 20(80%) patients from the second group who was treated by oral trimethoprim / sulfamethoxazole, also cleared and all the patients in the third group 25(100%) who were treated by a mixture of 5% permetherin topically and oral trimethoprim / sulfamethoxazole. Of those who were complicated by secondary bacterial infection 40(60%), 30(75%) the cultures shows growth of Staphylococus aureus, 6(15%) Streptococcus pyogenes and 4(10%) mixed growth of both Staph and Strep. The cultures which were tested by 5% permetherin shows no inhibition zone but those cultures which were tested by trimethoprim /sulphamethoxazol shows significant inhibition zone. It was concluded that permetherin was ineffective as antibacterial agent but it was highly effective as pediculocidal agent and it was more effective when combined with oral trimethoprim /sulfamethoxazol.