Capsella bursa pastoris ('Shepherd's Purse'), dried and ground, was added at rates of 20 and 40% to the stock diet of male and female mice. Diets similarly diluted with grass meal were used for comparison.
At the 40% level, both materials impeded ovulation and produced temporary infertility in males and females. 20% Capsella did not affect female fertility, and previous experiments had shown that an equivalent amount of grass meal was harmless.
Neither substance affected the establishment of vaginal patency in immature female mice or produced signs of oestrogenization in spayed animals.
The infertility produced was probably due to the high degree of dilution of the diet rather than to specific anti-fertility activity, but the latter possibility has not been excluded entirely.