Tertiary butylhydroquinone, TBHQ, is a chemical preservative used in food and petfood to delay the onset of rancidness and greatly extend the storage life of foods.

According to an article by Shona Botes on NaturalNews.com, the Food and Drug Administration allows amounts of up to 0.02% of the total oils in food to be TBHQ, but consuming high doses (between 1 and 4 grams) can cause nausea, delirium, collapse, tinnitus and vomiting. Long-term, high doses of TBHQ in laboratory animals have shown a tendency for the animals to develop cancerous precursors in their stomachs and begin to present DNA damage.