Black widows produce a toxin that affects the nervous system, and muscle pain and tightness of the chest are some of the most common side affects to a bite. Swelling can be seen in some extremities, but is rarely observed at the location of the bite. Other symptoms that may occur after being bite by a black widow is restlessness, sweating, difficulty with breathing and speech. While most symptoms are severe only the first day, some may continue for several weeks or a month after the bite, but after the first 2-3 days, the symptoms will usually decline. In most cases, black widow bites typically affect the extremely young or elderly more severely than the rest of the general population.