These two families are characterized by sharks with dorsal fin spines, which are not typical of most other families. Envenomations from this species occur when anglers handle struggling fish while attempting to remove the hook. Again, injuries are the result of stings while live specimens are handled. The toxin of venomous sharks is contained within the tissue embedded in a groove along the spine. Almost nothing is known about the toxic properties of the venom.
Experiments conducted on laboratory animals indicate the venom is comparatively mild.
Nonetheless, human envenomation can produce intense pain. Swelling of the injured area can persist for several days. Clinical reports claim some species of Squalus can induce fatal stings. This, however, remains unconfirmed. Pain can be relieved by soaking the wound in very hot water for 30 minutes or longer.