In some cultures opisthobranchs constitute part of the diet but in small proportions. For example, inhabitants of the Kuril Islands eat raw or cooked Tochuina tetraquetra, a local delicacy known as "Tochni" (Odhner, 1963). At the beginning of the 20th century, natives of central Chile used to eat species of Doris amarilla, but only in an act of desperation by the poorest members of communities (Schrödl, 1998). This same author reported that, in the area near Valdivia, Chile, nudibranch dorids are used in seafood dishes. After removing the viscera, this species is served raw with lemon and hot sauce or cooked with other seafood and vegetables.

The only commercial fishery of opisthobranchs is in the coastal regions of China, where the dry bodies of Aplysia are used for medicine (Thompson, 1976). The use of compounds extracted from opisthobranchs date back to Roman times. The search for chemical substances of pharmacological interest may become a very important business for the pharmaceutical and medical industry. Many of the defense chemicals found in opisthobranchs have been investigated by the National Cancer Institute in the United States for potential pharmaceutical uses (Flam, 1994). An example is Dolabella auricularia, from which Dolastatin 10 has been extracted, an agent that seems promising in the cure against cancer.

Opisthobranch mollusks are also used as models in neurological studies due to the great sizes of individual nerve cells. For most species of opisthobranchs, the potential use of the animal's secondary metabolites still has not been studied.