Abstract: The absorption, distribution and excretion of anthraquinone derivatives in animals and in human beings receiving single oral, intramuscular or intravenous doses were studied. The anthraquinone derivatives tested were easily absorbed and excreted. The peak blood levels were reached within 2—3 hours after oral ingestion. Thereafter, the concentration fell gradually. After intramuscular injection, the peak was reached within 30 minutes, the concentration fell rapidly and then maintained a nearly constant level for 4 hours. By the intravenous injection the peak was reached within 5 minutes. The concentration dropped quickly in the first 30 minutes. At the end of 1 hour, anthraquinone derivatives were not detectable in the blood. Among the anthraquinone derivatives studied, rhein was more easily absorbed than emodin. Anthraquinone derivatives were excreted by the bowel, urine and bile. The total excretion was about 46.2% of ingested does. About 23.4% was found in the feces and 22.8% in the urine. The excretion lasted 2 days. About 88% of that excreted in feces occurred in the first day and about 61% of that excreted in urine appeared in the first8 hours. Anthraquinone derivatives were distributed mainly in the liver and kidneys afterabsorption. No detectable amount was found in heart, spleen, lungs and brain.