The allergenicity of edible oils derived from sunflower seeds was investigated in two patients with anaphylactic sensitivity to sunflower seeds. Specific IgE-mediated hypersensitivity to sunflower seed was demonstrated by history, prick skin tests, positive passive transfer skin test, and RAST. Specific IgE directed toward sunflower oil, refined or cold pressed, could not be conclusively demonstrated. The Prausnitz-Küstner reaction with sunflower oils performed with one patient's serum was negative. Although the cold-pressed sunflower oil was found to contain a minute amount of protein, open challenge with the derivative oils resulted in no immediate or delayed reaction in the two patients studied. Sunflower oil ingestion in these patients who were highly sensitive to the parent material proved safe. Nonallergenicity of derivative products needs to be proven for each case.