Improvement in detecting the carcinogenicity of bracken fern using an Egyptian toad.

Neoplasms developed in 18 of 98 toads, Bufo regularis, subjected to enforced feeding with bracken fern. They comprise 7 cases of adenocarcinoma in the ileum, 16 cases of hepatomas in the liver and 6 cases of neoplasms in the kidney due to metastases from the hepatomas. The results demonstrate that the Egyptian toad can be considered as an advantageous model for detecting the carcinogenicity of bracken fern, since the lesions occur faster than in other experimental animals.