The dominant lethal effects of some ergot alkaloids.

The dominant lethal test was carried out in the mouse using the ergot derivatives dihydroergotoxine, ergotamine and methysergide. A significant increase in early fetal deaths was induced by 100 mg/kg of dihydroergotoxine and methysergide. Doses of 25 mg/kg and 50 mg/kg did not induce positive effects. Ergotamine was not effective in doses up to 100 mg/kg. Reduced numbers of implantations were not consistently observed following treatment with the ergot preparations, but some anti-fertility effects were noted. Cyclophosphamide, used as a positive control compound, produced significant effects in doses as low as 25 mg/kg.