Nigella sativa is a wonderful plant that gained worldwide recognition. The seeds of Nigella sativa L., it is known as black seed, black cumin or habatul Barakah. Among Muslims, black seed is the therapy for all illnesses except death in one of the Prophetic hadith. Thymoquinone is the main bioactive component of Nigella sativa essential oil, most of the therapeutic properties of this plant are dependent on it. The effect of Nigella sativa oil alone or in combination with praziquentel on S. mansoni infected mice is decreasing the total number of ova deposited in both the liver and the intestine