Overview
Most spider bites cause only minor injury. Bites from a few spider species can be dangerous.
When to seek emergency help
Get medical care right away if:
- You were bitten by a dangerous spider, such as a black widow or a brown recluse.
- You're not sure if the bite was from a dangerous spider.
- You have severe pain or stomach cramping.
- You have a wound at the bite site that's getting bigger.
- You're having trouble breathing or swallowing.
- The skin around the bite site is red, purple or brown, and swelling is getting bigger or has streaks spreading from it.
Treatment
To take care of a spider bite:
- Clean the wound at the bite site with mild soap and water.
- Put an antibiotic you can buy without a prescription on the wound three times a day. This helps you keep from getting an infection.
- Hold a cool cloth over the bite for 15 minutes each hour. Use a clean cloth that has been wet with water and squeezed mostly dry, or use a cloth filled with ice. The cool cloth helps lessen pain and swelling.
- If possible, raise the bite site area.
- Take a pain reliever you can buy without a prescription as needed.
- If the wound is itchy, it may help to take an antihistamine. Or try putting calamine lotion or a steroid cream you can buy without a prescription on the skin.
For pain and muscle spasms, your healthcare professional may prescribe pain medicine, muscle relaxants or both. You also may need a tetanus shot.
Black widow spiders
You can usually identify a black widow spider by the red hourglass marking on its belly. In the United States, this spider is more common in the South. It's also found in Europe.
Symptoms of a black widow spider bite can include:
- Irritated skin with pain and swelling.
- Severe stomach pain or cramping.
- Upset stomach, vomiting, headache, shaking or sweating.

Black widow spider
The black widow spider is known for the red hourglass marking on its belly.
Brown recluse spider
The brown recluse spider has a violin-shaped marking on its back, but this mark can be hard to see. This spider is commonly found in the southern half of the United States and in South America, where it is known as the brown spider.
Symptoms of a brown recluse spider bite can include:
- At first, a mild pain.
- Fever, chills and body aches.
- A blister or sore with a darkened, blue or purple center and a ring around it.

Brown recluse spider
The brown recluse spider is known for the violin-shaped marking on its back.