The Brown Recluse spider is not aggressive and normally bites only when crushed, handled or disturbed. It is aptly named since it is a reclusive creature seeking and preferring seclusion.

Fatalities are rare, but bites are most dangerous to children, elderly and those in poor physical condition.

Bite effects may be nothing at all, immediate or delayed. Some may not be aware of the bite for 2 to 8 hours, whereas others feel a stinging sensation usually followed by intense pain if there is a severe reaction. A small white blister usually rises at the bite site surrounded by a large congested and swollen area. Within 24 to 36 hours, a systemic reaction may occur with the victim characterized by restlessness, fever, chills, nausea, weakness and joint pain. The affected area enlarges, becomes inflamed and the tissue is hard to the touch. The spider's venom contains an enzyme that destroys cell membranes in the wound area with affected tissue generally sloughing away, exposing underlying tissues. Within 24 hours, the bite site can erupt into a "volcano lesion" (hole in the flesh due to damaged gangrenous tissue).