The absorption of the proteolytic enzyme bromelain was investigated in adult rats. Bromelain was labelled radioactively with 125-Iodine and intraduodenally applied. During the observation time of 6 hours blood- and lymphsamples were collected and their radioactivity measured. By radiochromatography high molecular protein could be separated from low molecular protein fragments. By means of a rabbit-anti-bromelainserum bromelain could be identified in the agar-double diffusion technique. Results show that adult rats can absorb bromelain up to 40% in a high molecular form. This observation explains the increased proteolytic activity in serum after oral application as well as the clinical effect concerning the treatment of edema or hematoma.