Several studies indicate that a plant-based diet protects against the development of some serious diseases. It is assumed that the antioxidant content in food is an important reason for this protection. Dietary plants contain several hundred antioxidants, many of which are believed to act in a synergistic way to protect the body against oxidative stress. Berries, fruits, spices and some nuts have proved to be excellent sources of antioxidants. In this preliminary study, many fruits and some seeds from Ugandan plants have been analysed for total antioxidant activity using the FRAP (Ferric reducing ability of plasma) assay. Our results demonstrate that there is a large variation in antioxidant activity between the samples analysed. The plants with highest activity in decreasing order were found to be: African black olive (Canarium sweinfurthii), pomegranate, guava, java plum (Syzygium cuminii), sweet banana, tamarind, mango, orange and passion fruits, with antioxidant values in the range of 47.25 to 0.77 mmol per 100 g fresh weight. We believe that increased awareness of antioxidant activity in food and resulting change in food intake can be of importance for an improved health situation.