On the basis of our previous reports on the DNA-increasing effect of L-carnosine, it was studied to observe its effect on the amount of RNA, DNA and proteins and DNA incorporation rate in some organs (brain, heart, kidney, liver, testis) : L-carnosine did not affect on the amount of RNA, DNA and proteins of each organ, but only in heart the amount of proteins was increased slightly. DNA incorporation rate in liver, heart and testis was increased markedly, but not increased in kidney and brain.