The effects of anti-oxidant of ether extract of red pepper peel were studied to compare with butylated hydroxyl toluene (BHT), citric acid and ascorbic acid. Peroxide and acid values of magarine irradiated with the sunlight were detected. The results were as follows: 1. The extract of red pepper peel influenced as antioxidant of magarine. But the extract was lower anti-oxidative effect than that of BHT at the same concentrations. The anti-oxidative effect increased with the concentration of the extract applied. 2. There was no synergistic and anti-oxidative effects, when the extract was used together citric and ascorbic acids. 3. The peroxide value of fermented magarine was controlled by the addition of the extract and BHT. However acid value of it was not controlled as much as peroxide value.