2-Hydroxy-3-methylbutyric acid (2-hydroxyisovaleric acid) is a metabolite found in the urine of patients with phenylketonuria methylmalonic acidemia propionic acidemia 3-ketothiolase deficiency isovaleric acidemia 3-methylcrotonylglycemia 3-hydroxy-3-methylglutaric acidemia multiple carboxylase deficiency glutaric aciduria ornithine transcarbamylase deficiency glyceroluria tyrosinemia type I galactosemia and maple syrup urine disease.

SUDAN ORANGE G is a natural product.

Bruceine D from Brucea javanica, may have the potential to be used as a natural viricide, or a lead compound for new viricides.