Some argue that high vitamin A levels in cod liver oil is a risk
for hypervitaminosis A. However, if you are an adult, you would have to be consuming excessive amounts of cod liver oil for years to reach toxic levels.
On October 8th, the Michigan State University (MSU) Diagnostic Center
for Population and Animal Health (DCPAH) revealed that it had identified 16 cases of confirmed
hypervitaminosis D (vitamin D toxicity) in dogs from 8 states (Michigan, Texas, Colorado, Wisconsin, California, Illinois, North Dakota and Utah).