Para-aminobenzoic acid is a naturally occurring substance that can absorb ultraviolet (UV) light. It is often used in sunscreen products, including lip moisturizers containing sunblocks. It is harmful in large amounts. It can also cause an allergic reaction in some people.

Para-aminobenzoic acid is found in certain lip balm and moisturizers containing a sunblock. Chapstick is one brand name.

Symptoms include:

• Diarrhea
• Eye irritation (if the product touched the eye)
• Intestinal blockage
• Nausea and vomiting
• Shortness of breath (with extremely high doses)

If you have an allergy to a dye in the moisturizer, you may develop tongue and throat swelling, wheezing, and trouble breathing.

DO NOT make a person throw up unless told to do so by poison control or a health care professional.

If you have an allergic reaction, call 911 or the local emergency number.

Determine the following information:

• The person's age, weight, and condition
• The name of the product (ingredients and strengths, if known)
• The time it was swallowed
• The amount swallowed

Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the container with you to the hospital, if possible.

The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Blood and urine tests will be done. The person may receive:

• Activated charcoal to prevent the poison from absorbing into the digestive tract
• Fluids through a vein (by IV)
• Medicines to treat symptoms

For an allergic reaction, the person may need:

• Airway and breathing support, including oxygen. In extreme cases, a tube may be passed through the mouth into the lungs to prevent aspiration. A breathing machine (ventilator) would then be needed.
• Chest x-ray.
• ECG (electrocardiogram, or heart tracing).
• Medicines specifically for allergic reactions.

Recovery is very likely. The ingredients are generally considered to be nontoxic.

Chapstick poisoning

Marcdante KJ, Kliegman RM, Schuh AM. Poisoning. In: Marcdante KJ, Kliegman RM, Schuh AM, eds. Nelson Essentials of Pediatrics. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 45.

Meehan TJ. Care of the poisoned patient. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 135.

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.