Poisonous Bites


California is home to many critters, insects, and spiders that bite. Bites vary in severity based on the person, type of bite, and the bite site. Most bites lead to unpleasant reactions such as an itchy bump. However, you may have stronger, life-threatening reactions if you are allergic to the venom (see anaphylaxis below). Venom is considered a poisonous substance created by critters, insects, and spiders. Learn how you can stay safe and prevent poisonous bites by following the tips below.

Bite precautions

  • Mosquitoes may carry West Nile Virus. If fever, headaches, and nausea occur from a mosquito bite, contact your physician immediately.
  • Rattlesnake bites are life-threatening. If bitten by a rattlesnake call 9-1-1 immediately.
  • Spider bites (example: Black Widow) can result in uncomfortable to severe symptoms. If you are concerned about your symptoms, call the California Poison Control System for advice. If your symptoms are severe, go to the emergency room.
  • Ticks can carry Lyme disease and if fever, rash, or vomiting occurs, you should also contact your physician immediately.

General bite symptoms

  • Fever
  • Hives
  • Pain/Itching
  • Redness
  • Swelling
  • Warmth around the bite site

Rattlesnake bite symptoms

Spider bite symptoms

  • Dizziness
  • Fever/Chills
  • Headache
  • Pain/Itching
  • Redness
  • Stiffness
  • Stomach pain or cramping
  • Swelling


Anaphylaxis is a severe, potentially life-threatening allergic reaction. Call 911 right away if you have any of the following symptoms.

  • Chest tightness
  • Difficulty breathing or wheezing
  • Difficulty talking or confusion
  • Pale or red face
  • Rash over the whole body
  • Sever pain, cramping, or swelling
  • Shock
  • Spreading redness or red streaks

First aid tips

  • For bites
    • Cleanse the site with soap and water
    • Use an ice pack to reduce pain or swelling
    • Reasons to go to the doctor after a spider bite include severe discomfort, spreading local redness accompanied by pain, and any drainage from a bite site
  • For anaphylaxis
    • Use an EpiPen (epinephrine autoinjector) right away. If you do not have one, call 911 immediately.

Prevent poisonous bites

If you come across critters, insects, or spiders, keep your distance.

General bites prevention

  • When outdoors, apply insect repellants that contain DEET to all exposed skin areas
  • Wear protective clothing for yard work or around grassy areas, such as:
    • Hats
    • Long sleeves and long pants
    • Gloves
    • Closed-toe shoes

Rattlesnake bite prevention

Spider bite prevention

  • Do not agitate spiders. They typically only bite if they feel threatened.
  • Keep cribs and beds as far from walls as possible.
  • Before getting dressed, shake out clothing, shoes, and hats that you have not worn for a while.
  • If a bed has not been slept in for awhile, check the sheets and covers thoroughly before climbing in.
  • Always put on gloves and long-sleeved shirts when going through or emptying closets, boxes, containers, or when handling fire wood, lumber, and any items you have been storing for a long time.
  • Clean and get rid of clutter in the basement, attic, garage, storage, and closets in and around your home.
    • Remove spiderwebs and spiders.
    • Dust and vacuum around windows, corners of rooms, under furniture, and in storage areas.

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