 Animals that ingest smaller amounts of PCBs in food over several weeks or months develop various health effects, including anemia; acne-like skin conditions (chloracne); liver, stomach, and thyroid gland injuries (including hepatocarcinoma), and thymocyte apoptosis.Other effects of PCBs in animals include changes in the immune system, behavioral alterations, and impaired reproduction.PCBs that have dioxin-like activity are known to cause a variety of teratogenic effects in animals.