An extract of Scutellaria barbata D. Don is effective in the arrest of cancer cell growth in the G1 phase, the induction of apoptosis in cancer cells and the shrinking of solid cancers. The extract may be prepared as a pharmaceutical composition for administration to mammals for the treatment of solid cancers, such as epithelial cancers. Such epithelial cancers include breast cancer and ovarian cancers. The extract is obtained from Scutellaria barbata D. Don by contacting aerial portions of a plant from the species Scutellaria barbata D. Don with an aqueous or alcoholic solvent.