Most basal-cell carcinomas of the skin are readily detectable and, being accessible, can be successfully treated either surgically or radiologically. In some few patients, however, lesions may be so numerous or attain such large size that attempts to eradicate the lesions by either of the above means meet with certain failings or shortcomings. In such cases the trial use of selected chemotherapeutic compounds seems warranted. A number of chemical agents are known to have at least some measurable inhibitory effect on the growth or progression of some cancers in man. None, however, affect sufficient numbers of different types of cancers to warrant their general therapeutic use. Among the compounds that have been subjected to clinical trial to date, the folic acid antagonists have produced, in both normal and neoplastic tissues, changes that seem to be significant enough to attract particular attention. In 1948, Farber et al.1 reported that aminopterin