The influence of dyes with special affinity to amyloid on the resorption of experimental amyloidosis was studied in mice (A/J/Bom). 2. The amyloidosis was produced by injections of 5% casein over a period of seven weeks. After an interval of six weeks the animals received 0.5 ml of a 0.01% dye solution intraperitoneally (congo red, diamine green, Evans blue) or 0.9% NaCl (controls) every seventh day over a period of 22 weeks. 10, 17, and 22 weeks after the dye treatment was started 3-4 animals of each group were sacrificed and studied histologically. 3. In contrast to the in vitro findings of Shirahama et al. (1971), in vivo there is no acceleration of amyloid resorption by congo red. In the same way diamine green does not accelerate the resorption of amyloid. Evans blue produces a decrease in the amount of amyloid, but at the same time it causes wasting in the animals. Moreover, congo red and diamine green produce amyloidosis by themselves. 4. From our findings neither congo red nor the other amyloidaffine dyes studied, diamine green and Evans blue, are suitable for a therapy of amyloidosis.
