When a drug company learns of a new, important risk in one of its medicines, it sends doctors and pharmacists a Rote-Hand-Brief, a red-hand letter. A red hand is printed on the envelope and on the letter. The duty rests on the German Medicines Act. The company sends the letter on its own responsibility, but the federal drug authority agrees its content and its recipients first. The letter may report a new reason not to use a drug or a new warning. One such letter, in February 2024, concerned the drug valproate. It warned of a possible risk of neurodevelopmental disorders in children whose fathers had taken it. Letters that bring no new risk are called Informationsbriefe. They do not carry the red hand.