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We, the undersigned scientists and physicians, demand that all genetically engineered (GE) foods be withdrawn from the market unless they have undergone rigorous safety assessment including long term testing on animals and humans. This includes all GE foods that have been approved on the basis of the principle of "substantial equivalence".

In practice, all GE foods on the market have been insufficiently tested and should thus be withdrawn.

The reasons are as follows:

The principle of "Substantial equivalence" is based on the assumption that if a GE food and its natural counterpart are compared for a limited number of chosen traits, and are found to be similar, then there is no reason to submit the GE food to careful testing.

This assumption has no basis in science. It does not take into account the possibility that in each separate case, insertion of genes into DNA may cause metabolic disturbances, or unpredictably generate potentially harmful substances. This has been predicted on molecular biological grounds [1] [2] [3] and also demonstrated in experimental cases [4]. Especially slowly acting harmful substances may be very difficult to detect. Thus there is a considerable risk they will be overlooked if the superficial tests used for "establishing substantial equivalence" are applied.

The insufficiency of the principle of substantial equivalence is briefly summarized in a web document [5] and is explained in more detail in a recent article in the science journal "Nature" [6]. Only by applying rigorous food safety testing, including long term testing on animals (preferably lifetime) and humans (at least 3-5 years), is it possible to minimize the risk of missing unpredicted harmful substances [7].


The principle of substantial equivalence has no scientific basis. Since this is the standard which has been used for approving GE foods, it follows that none of the GE foods on the market today can be considered safe. In the worst case exposure of the population may have disastrous consequences. Therefore, GE foods at present on sale should be withdrawn from the market immediately. No new GE foods should be introduced until proper methods of assessment have been applied.


1. Antionou M, Cummins J, Daniel EE, Epstein S , Howard C V, Orskov B, Pusztai A, Raghuram N, Seralini G-E, Wuerthele S. "The safety of GE foods. Reasons to expect hazards and the risk for their appearance" at http://www.psrast.org/defknfood.htm

2. Fagan J, "Assessing the safety and nutritional quality of genetically engineered foods" at http://www.psrast.org/jfassess.htm

3. National Research Council (USA), . "Genetically Modified Pest Protected Plants". p. 137 (Washington, D.C.: National Academy Press, 2000). ISBN 0309069300. On-line copy at: http://www.nap.edu/html/gmpp/

4. a) Violand BN et al. Protein Science. 3:1089-97, 1994. b) Reddy SA, Thomas TL.Nature Biotechnology, vol 14, sid 639-642, May 1996. c) Inose, T. Murata, K. Int. J. Food Science Tech 30: 141-146, 1995. d) Nordlee, J.A. et al. The New England Journal of Medicine 14: 688-728; 1996.

5. PSRAST, "Inadequate safety assessment of GE foods" at http://www.psrast.org/subeqow.htm

6. Millstone E, Brunner E and Mayer S, "Beyond Substantial Equivalence", Nature 401: 525-526, 7 Oct 1999.

7. Fagan J, "Testing the safety of genetically engineered foods" at http://www.psrast.org/jfreqtst.htm

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List of signatories

"Genetically Engineered Food - Safety Problems"
Published by PSRAST

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