Abstract: Two kinds of fertilized ova were collected .in vivo and in vitro fertilized ova. All the ova were incubated with 0, 0.25, 0.5, 2.5 and 5.0 μg/ml Pentamidine isethionate (PI) for 15 min, respectively. After drug treatment. the fertilized ova were further cultured for 28 h to investigatethe cleavage of ova. The results showed that the cleavage of fertilized ova in the PI-treated groupswere significantly reduced in normal cleavage and increased in abnormal cleavage as compared tothose in the controls (p<0.01). It may be concluded that PI possesses an antifertility effect.

Key words: Pentamidine isethionate, Fertilized ova, Cleavage