Further studies of two polymerized preparations of ragweed antigen containing large amounts of ragweed antigen E were done. The results demonstrated that the rate of absorption of the polymerized materials from skin sites was diminished. The disappearance of the monomer and polymers from the vascular compartment was also different with the monomer appearing most rapidly in the urine, the high molecular weight polymer in the liver and spleen and the lower molecular weight polymer being retained the longest in the circulation. The polymerized ragweed preparations elicited histamine release from human peripheral blood leukocytes but required significantly higher concentrations for the same degree of release. An even larger comparative dose of the polymerized preparations was necessary to elicit cutaneous reactivity. The polymerized ragweed preparations reacted with the neutralized IgE antibody against ragweed antigen E in vitro requiring somewhat different weight ratios of the polymerized forms. The results demonstrate characteristics of these preparations which suggest potential usefulness in immunotherapy of ragweed pollenosis.