Extracts of Agave schottii Engelm. (Amaryllidaceae) were shown to be effective inhibitors of the Walker carcinoma 256 (intramuscular) tumor system of the CCNSC. The active material was shown to be saponin. By means of a Silica Gel G dry-column technique, an effective separation of the acetates of the saponins present was accomplished. Gitogenin was identified as the genin of all saponins present. While the sugar associated with the saponin showing the highest degree of activity was galactose, the sugars associated with the three other saponins were identified as a mixture of galactose and glucose.