An in vitro study performed on HT-29 human colorectal carcinoma cells demonstrated the increase in mRNA expression levels for apoptotic genes such as caspase-3, caspase-8, Bax, and the reduction in the p53 gene expression after exposure to aqueous and ethanolic extracts of Epilobium parviflorum Schreb. The gene discussed is CASP3; the disease is colorectal carcinoma.