Stella Maudine Nickell (née Stephenson; born August 7, 1943) is an American woman who was sentenced to ninety years in prison for product tampering after she poisoned Excedrin capsules with lethal cyanide, resulting in the deaths of her husband, Bruce Nickell, and Sue Snow. Her May 1988 conviction and prison sentence were the first under federal product tampering laws instituted after the 1982 Chicago Tylenol murders.