Bioactivity of the extract from various processed garlic was evaluated based on the inhibition of lipoxygenase(LPO), and the effect of some stabilizers on the bioactivity was investigated. Water, ethanol or chloroform extract of 30 min boiled garlic showed 75%, 76% or 70% inhibition, respectively, compared to extracts of fresh garlic. In pickled garlic, LPO inhibition decreased gradually during storage. Chloroform extract of 40 day-stored pickled garlic inhibited LPO by 77%, and even on 60th day storage it still retained inhibitory effect of 73%, compared to that of fresh garlic. Meanwhile, the powdered (freeze-dried) garlic showed more bioactivity(80%) than the other processed garlics, and moreover, the irreversible/unstable components seem to be stabilized by freeze-drying. The optimum pH for stabilization of bioactive components in garlic macerate was pH 3 for 48 hr incubation and pH 11 for 6 hr incubation. In addition, the effect of NaCl was not so great, although but maximal stabilization was observed at 150mM. Stabilizing effect of α-tocopherol was markedly great, and at 6mM it showed 308% stabilizing effect after 48 hr incubation. More stabilizing effect was observed at lower concentrations of ascorbic acid(≤0.6mM) than higher concentrations. The stabilizing effect of soybean oil was found to be remarkable only during initial period(6 hr) of incubation.