YOUR correspondent Thomas Bromley (You Say, December 3) is probably correct in saying that most prescription drugs have been developed, as well as tested, using animal studies.

However, he does not mention the significant number of these which had subsequently to be withdrawn following serious side effects not predicted by the studies.

Some of the best known examples are Thalidomide, given to pregnant women, resulting in thousands of birth defects, and the arthritis drug Opren.

Mr Bromley appears to believe that "what happens in a living body" can be deducted from animal studies. Varieties of animals differ from each other and results of experiments on one species cannot be extrapolated to another or to humans.

There are alternatives to animal experimentation, and the Dr Hadwen Trust commissions medical research using these alternatives. You can get in touch with them at 84A Tilehouse Street, Hitchen, Herts SG5 2DY.

STAN BROWN,

Swinton Lane,

Worcester.