The US National Institutes of Health (NIH) has strictly limited its employees' ties to pharmaceutical and biotechnology companies. A group of leading NIH scientists, called the Assembly of Scientists, has complained that the new rules should be relaxed so as not to discourage scientists from working at the institutes.

The rules, announced by the NIH director, Dr Elias Zerhouni, say that senior scientists (about 5000 people) must not consult for pharmaceutical or biotechnology companies and must sell any shares or stock options that they or their families hold in such companies. They may not receive awards of more than $200, although the Lasker and Nobel awards are acceptable, and …