Post-coital contraceptive efficacy of the seeds of Nigella sativa in rats.

Hexane extract of the seeds of Nigella sativa L. prevented pregnancy in Sprague-Dawley rats treated orally at 2 g/kg daily dose on days 1-10 post-coitum. Significant antifertility activity was also observed in its column fractions and subfractions. At contraceptive dose, the active hexane extract exhibited only mild uterotrophic activity comparable almost to 0.002 mg/kg dose of 17 varies; is directly proportional to-Ethinylestradiol, but was devoid of any estrogenicity in the immature rat bioassay.