AbstractA search was made for new degradative pathways for glucosyl and galactosyl ceramides in an effort to explain the failure of these lipids to accumulate in the brains of children with Krabbe's or Gaucher's disease. Using various buffers and incubation conditions, we tested brain homogenates from 12 day old rats with the stearate‐labeled and galactose‐labeled lipids. No evidence for direct deacylation (and formation of psychosines) could be obtained, nor was there any evidence for transacylation of sphingocyl phosphoryl choline or oxidation of the 6 position of the galactose moiety. Two new derivatives of galactosyl ceramide were observed, possibly fatty acid esters of unknown polar compounds. It is tentatively proposed that the etiology of infantile Krabbe's and Gaucher's diseases involves, not an accumulation of galactosyl and glucosyl ceramides, with consequent formation of toxic products, but rather malfunction of some other role of the corresponding glycosidases.