The effects of adriamycin (Adr) and cisplatin on body weight, organ weight, and the contents of putrescine, spermidine and spermine in 15 different tissues were examined in rats that had been given these drugs for 5 days. The weight of the spleen in cisplatin-treated rats, and of the thymus, spleen, kidney and heart in Adr-treated rats showed statistically significant decreases. Neither Adr nor cisplatin should be used to treat cancers in the seminal vesicle, and Adr should not be used to treat those in the large intestine due to significant increases in spermidine and spermine, which are associated with a risk of re-growth. However, Adr is recommended in the treatment of cancers in the thymus, kidney, skeletal muscle (femoral), heart, prostate, testis, liver, small intestine and lung, based on decreases in some of the polyamines, while cisplatin is not recommended in the thymus, kidney, skeletal muscle or heart for the same reason that Adr is not recommended to treat cancers of the large intestine (rectum). The ratio of spermidine to spermine was significantly higher in the skeletal muscle of cisplatin-treated rats and in the small intestine and brain of Adr-treated rats, and was lower in the prostate, seminal vesicle and spleen of Adr-treated rats than in control rats.