Cassava (Manihot esculenta Crantz) is a known source of linamarin, but difficulties associated with its isolation have prevented it from being exploited as a major source. A batch adsorption process using activated carbon proved successful in its isolation, with ultrafiltration playing a pivotal role in its purification. Thirty-two minutes of contact time was required for 60 g of extract, yielding 1.7 g of purified product. Picrate paper, infra-red and 'HNMR analysis confirmed the presence and structure of linamarin. Cytotoxic effects of linamarin on MCF-7, HT-29 and HL60 cells were determined using the MTT assay. Cytotoxic effects were significantly increased in the presence of linamarase (P-glucosidase), with a 10-fold decrease in the IC50 values obtained for HL-60 cells. This study thus describes a method for the isolation and purification of linamarin from cassava, as well as its cytotoxicity potential.