RESUMEN
The anthelmintic activity of santonin was investigated in naturally infested sheep with gastrointestinal nematodes, a total number of 27 adult sheep [1-2 years old] were used in this study. The animals were allocated into 3 groups [noninfested nontreated control group, noninfested treated control group and infested treated group], each of 9 animals and maintained in clean and parasite free pens. The clinical signs observed in infested sheep were inappetence, dullness, anemia, soft feces and /or diarrhea and sometimes edema of the interm and ibular space. The clinical, parasitological, hematological and biochemical data of the different groups of sheep reflexed a very good efficacy of santonin as a new anthelmintic controlling parasitic gastroenteritis in sheep. Data also confirmed the safety of the drug at a dose rate of 20 mg/kg body weight orally. The application of santonin as a new anthelmintic in veterinary field can overcome anthelmintic resistance by anthelmintic rotation. Moreover, it is economically cheap as it can be easily extracted from the Artemisia herba-alba which is widely grown in Egypt