A cream formulation containing high concentrations (10%) of a standard mixture of solasodine glycosides (BEC) has been shown to be effective in the treatment of malignant and benign human skin tumours. We now report that a preparation (Curaderm) which contains very low concentrations of BEC (0.005%) is effective in the treatment of keratoses, basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin of humans. In an open study, clinical and histological observations indicated that all lesions (56 keratoses, 39 BCCs and 29 SCCs) treated with Curaderm had regressed. A placebo formulation had no effect on a smaller number of treated lesions. Curaderm had no adverse effect on the liver, kidneys or haematopoietic system.