Iron(II) fumarate, also known as ferrous fumarate, is the iron(II) salt of fumaric acid, occurring as a reddish-orange powder, used to supplement iron intake.

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.

16-Oxoalisol A is a natural product.