Aminopterin is the rodenticide identified in the recall pet foods. It was used in the 1950's as an abortion drug with poor results. It was also used by Dana Farber as an anti cancer drug. There were recent clinical trials with children who have acute leukemia. They took this drug weekly. The conclusion of the trials was that aminopterin deserves further study as a potent alternative to methotrexate.
Clinical Cancer Research Vol. 11, 8089-8096, November 15, 2005
Yes it is still bad stuff for pets but its seems to be not all bad depending on the situation.
