The anti-inflammatory effects of phlorotannins identified in the hydrophilic fraction of the brown alga, Eisenia arborea, were previously determined in vivo and in vitro. Here, we investigated the in vivo effect of the lipophilic fraction from this alga in mice. In ICR mice, ear swelling was induced by three sensitizers: arachidonic acid (AA), 12-O-tetradecanoylphorbol-13-acetate (TPA) and oxazolone (OXA). Swelling induced by AA or TPA was suppressed in a dose dependent manner after the said lipophilic fraction was applied to the mouse ears at a dose of 0.01, 0.1 and 1 mg/mouse, respectively. The suppression was similar to that by epigallocatechin gallate (EGCG), a typical natural inhibitor. On the other hand, the suppressive effect of the fraction at 1 mg/mouse on ear swelling induced by OXA was significantly lower than that of EGCG (p < 0.01). At a dose of 0.01 and 0.1 mg/mouse, no suppression by the fraction was observed. Therefore, lipophilic active components in the fraction may suppress immediate inflammatory reactions induced by AA or TPA, but not show suppressive effects on the delayed-type (type IV allergy) inflammatory reactions induced by OXA.