Umbelliferone occurs in many familiar plants from the Apiaceae (Umbelliferae) family such as carrot, coriander and garden angelica, as well as in plants from other families, such as the mouse-ear hawkweed (Hieracium pilosella, Asteraceae) or the bigleaf hydrangea (Hydrangea macrophylla, Hydrangeaceae, under the name hydrangine).

Umbelliferone absorbs strongly at 300, 305 and 325 nm, with log ε values of 3.9, 3.95 and 4.15 respectively, and it fluoresces blue in both ultraviolet and visible light.

The powerful absorption at three different wavelengths, coupled with the fact that the energy is dissipated safely as visible light, make umbelliferone a useful sunscreen agent.

The ultraviolet activity of umbelliferone led to its use as a sunscreen agent, and an optical brightener for textiles.

[citation needed] Umbelliferone is a potent inhibitor of type 3 17β-hydroxysteroid dehydrogenase, the primary enzyme responsible for the conversion of 4-androstene-3,17-dione to testosterone, with IC50 of 1.4 μM.

O-Glycosylated derivatives such as skimmin (7-O-β-D-glucopyranosylumbelliferone) occur naturally and are used for the fluorimetric determination of glycoside hydrolase enzymes.

Isoprenylated derivatives are also widespread, such as marmin (found in grapefruit skin and in the bark of the Bael tree) and furocoumarins such as marmesin, angelicin, and psoralen.