International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

19: Safe Antibiotics Fatal Flaw

Animal experiments suggested that chloramphenicol was a very safe drug but clinical experience soon revealed serious side-effects making it no longer suitable for internal use, except for life-threatening infections such as typhoid fever. In France, chloramphenicol has been completely withdrawn.(1)

In 1952, physicians in Baltimore drew attention to chloramphenicol's effects on nerve cells in the body.(2) They described a patient who almost became blind and who suffered such severe pain in her feet that she could only walk with the aid of pain-killing narcotic drugs. She had been taking chloramphenicol for 5 months. This was the first of many cases of optical and peripheral neuritis caused by chloramphenicol yet animal experiments had shown the drug to be practically free of side-effects, even after prolonged administration.(2)

Even more seriously, the drug caused aplastic anaemia, an often fatal blood disease sometimes terminating in leukemia. Once again, the effect had not been predicted by animal tests, and the British Medical Journal records how chloramphenicol produced nothing worse than transient anaemia in dogs when given the drug for long periods by injection, and nothing at all when given orally.(3)

Today we know that chloramphenicol's deadly side-effect can be identified by test-tube studies with human bone marrow cells.(4)


1) C.Spriet-Pourra & M.Auriche, Drug Withdrawal from Sale (PJB Publications,1988).
2)L.Wallenstein & J.Snyder,Annals of Internal Medicine, 1952,vol.36, 1526-1528.
3) British Medical Journal, 1952, July 19, 136-138.
4) G.M.L.Gyte & J.R.B.Williams, ATLA, 1985, vol.l3, 38-47.

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