Various concentrations of chilli extract were tested in 2 stages on the growth of a human buccal mucosa fibroblast cell line. Firstly, concentrations of 25, 75, 150 and 300 micrograms/ml were tested on the cell line for 6 days followed by a repeat which included concentrations of 400 and 500 micrograms/ml. In the latter, cell growth was monitored for 18 days. From day 3 (72 hr) suppression of cell growth was evident with concentrations 300-500 micrograms/ml. Total cell death occurred at 16 days with 300 micrograms/ml and at 6 days with 400-500 micrograms/ml. With the lower concentrations, 25-150 micrograms/ml, the daily counts were lower than the control but the difference was not statistically significant. Growth continued unabated. It is therefore concluded that cytopathic effect of chilli extract to fibroblasts is concentration dependent.