Black widow bites are rarely fatal unless you are allergic to them. There is an antivenom, but it can only be used once in a lifetime. Not quite sure why. However, back to the bite. The descriptions of black widow bites are excruciating, but only make you wish you were dead. Having been bitten you will build up a tolerance against the results of future bites.

More to be aware of are brown recluse bites which can cause many problems including messing with your heart.

Both are considered as part of the cobweb spider family.

Hope this helps.