In the course of a search for tumor necrosis factor $(TNF)-{alpha}$ inhibitory compounds from medicinal plants, we identified neolignans, honokiol and magnolol, from the alcoholic extract of Magnolia offcinalis as active inhibitory principles. These compounds dose-dependently inhibited $TNF-{alpha}$ production without displaying cytotoxicity and their inhibitory activities measured by $IC_{50}$ values were 53.7 and $61.4;{mu}M$, respectively.