A+ PRACTICAL ABSTRACT: An investigation was commenced in order to observe the effect a change of temperature will have on the activity of the enzyme catalase, present in capsicum extract. Enzymes are biological catalysts which speed up the rate of reaction in all living organisms, and have specific conditions which will determine how productive they are. Samples of capsicum extract were exposed to hydrogen peroxide at different temperatures, and the amount of catalase activity was compared by measuring the amount of oxygen gas produced in each case using the volume of the foam as an indicator. It was hypothesised that the enzyme catalase will have an optimum temperature of around 35°C, with function decreasing either side of this. From the results, it was concluded that the hypothesis was not supported, and the enzyme catalase was working more optimally at a lower temperature compared to a higher temperature.