Introduction:     Although antifertility and different aspects of Abrus precatorius  seed have been

I studied but  duration of antifertility  effect and its relevance with  "day of administration" after matting is not clear.

Materials  and  Methods:  To clarify this,  10 mg/mice etheric extract of A. precatorius  seed was injected I.P. 1st-5th day after matting.

Results: In mice, the injection of extract at 1st, 2nd, 4th and 5th day of matting showed antifertility effect in the first reproductive cycle. The secondary day administration of the seed extract was ffective for two reproductive cycles.

Conclusion: The antifertility mechanism of seed extract on different days is not the same and may included anti-implantation (4th and 5th day of matting), oxytocic (4th and 5th day of matting)

and rapid passage of ovule from oviduct (1st and 2nd day of matting).