November 17, 2008

Dear Doctor,

As a key customer and valued stakeholder in the IDEXX Laboratories' feline business, we want to inform you that IDEXX Laboratories, Inc. and its affiliates sold its Acarexx® (0.01% ivermectin) otic suspension and PZI VET® (protamine zinc insulin) pharmaceutical franchises to Boehringer Ingelheim Vetmedica, Inc. (“BIVI”), a leading animal health pharmaceutical company, on November 14, 2008.

You can continue to order Acarexx as you do today, since IDEXX and Boehringer Ingelheim share the same distributors. Boehringer Ingelheim is committed to providing you with a continued high level of customer service and product innovation. For BIVI product technical assistance, call 1-866-638-2226 and for product orders and customer service, call 1-800-325-9167.

The decision to sell these products allows IDEXX to concentrate on our core businesses of reference laboratory testing, in-hospital diagnostics, digital imaging, and practice management software. We have confidence that the additional focus on these core businesses will generate a broader array of new products that will provide practitioners with opportunities to improve animal health care.

Thank you for your past support of our feline pharmaceutical products, and we look forward to our continued relationship.

IDEXX Laboratories, Inc.