Coal-tar poisoning is often caused by chewing on or eating items that contain coal tar. Typical sources are clay pigeons, tar paper, creosote-treated wood, and bitumen-based flooring. Effects include liver damage with signs of jaundice, fluid build-up within the stomach, anemia, and death.

Coal tar contains 3 toxins: phenol, cresol, and pitch. Phenol is the most important toxin in coal-tar products. Cresols are used as disinfectants and are readily absorbed through the skin. Cats are especially sensitive to both phenol and cresol. Because cresol is toxic to wood-destroying fungi and insects, it is used as a wood preserver. Pitch is used as a binder in clay pigeons, road asphalt, insulation, tar paper, and roofing compounds. It is also used to cover iron pipes and to line wooden water tanks.

Diagnosis of coal-tar poisoning requires excluding poisoning by toxic plants and deficiency of vitamin E or selenium. Fragments of clay pigeons, tar paper, or other sources of coal tars found in the gastrointestinal tract, or chemical detection of coal-tar products in the liver, kidneys, blood, or urine can confirm the diagnosis.

There is no specific antidote for coal-tar poisoning. Supportive treatment is helpful, along with activated charcoal and medicines that cause the bowels to empty to reduce absorption. Antibiotics and high-quality protein diets may help recovery.

Last full review/revision July 2011 by Barry R. Blakley, DVM, PhD; Cheryl L. Waldner, DVM, PhD; Rob Bildfell, DVM, MSc, DACVP; William D. Black, MSc, DVM, PhD; Herman J. Boermans, DVM, MSc, PhD; Cecil F. Brownie, DVM, PhD, DABVT, DABT, DABFE, DABFM, FACFEI; Raymond Cahill-Morasco, MS, DVM; Keith A. Clark, DVM, PhD; Gregory F. Grauer, DVM, MS, DACVIM; Sharon M. Gwaltney-Brant, DVM, PhD, DABVT, DABT; Larry G. Hansen, PhD; Safdar A. Khan, DVM, MS, PhD, DABVT; Garrick C. M. Latch, MASc, PhD; Gavin L. Meerdink, DVM, DABVT; Lisa A. Murphy, VMD; Frederick W. Oehme, DVM, PhD; Gary D. Osweiler, DVM, MS, PhD, DABVT; Mary M. Schell, DVM; David G. Schmitz, DVM, MS, DACVIM; Norman R. Schneider, DVM, MSc, DABVT