A person with a black widow spider bite has an injury to the skin that may, or may not, contain venom. Black widow spiders are the most venomous spiders found in the US. This spider is jet black with a red hourglass shape on the underside.

Black widow spiders occasionally bite people when their territory is threatened. These spiders like dark, protected locations such as under rock, logs or outdoor toilet seats. Despite their potent venom, the bites are rarely fatal.