Food Safety

What Is Red Dye 40: A Complete Guide

What Is Red Dye 40: A Complete Guide
iStock; Everyday Health
By
Published on January 30, 2025
by
Red Dye 40 (also known as Red 40) is the most widely used synthetic food coloring used in the United States. More than 36,000 American food products — including candies, sodas, and cereals — contain this dye.

The U.S. Food and Drug Administration (FDA) approved Red Dye 40 for use in food in 1971, but has not reevaluated it for health risks in years even as consumer advocacy groups have voiced concerns.

In the fall of 2024, the state of California led the nation by enacting the first ban of Red 40 along with five other dyes in foods served in public schools.

Robert F. Kennedy Jr., President Donald Trump’s pick for U.S. Health and Human Services secretary, has also vowed to crack down on food dyes such as Red 40.

Even more scrutiny has been directed at Red 40 after the FDA banned the use of Red Dye 30 in foods and ingested drugs in January 2025.

With health concerns swirling around the food dye, here’s what you need to know about this synthetic ingredient.

What Is Red Dye 40 Used For?

As with all food colorings, Red Dye 40 is added to foods, drugs, and cosmetics in order to make these products more attractive, appealing, appetizing, or easily identifiable.


Companies use synthetic dyes rather than natural ones because they can be mass-produced at a fraction of the cost of gathering and processing natural materials.

Red Dye 40 is derived from petroleum or crude oil, and treated with other chemicals in a process to make it ingestible.

Which Food Additives Are Banned In Europe But Still Used in the U.S.?

Discover which food additives are banned in Europe but still used in the U.S.
Which Food Additives Are Banned In Europe But Still Used in the U.S.?

Next up video playing in 10 seconds

Is Red Dye 40 Safe?

While ingesting small amounts of Red Dye 40 seems unlikely to affect overall health, a growing body of research suggests it may be connected with a number of issues.

Behavioral Issues in Children

Some research has linked Red 40 to increased hyperactivity and behavioral changes in some children, particularly those diagnosed with ADHD (attention deficit hyperactivity disorder), potentially worsening symptoms like difficulty sitting still, excessive talking, anxiety, moodiness, and irritability.

Countries in the European Union require foods containing Red 40 and other synthetic dyes to carry a warning saying that these products “may have an adverse effect on activity and behavior in children.”

"There's pretty good evidence at this point indicating a small but significant deleterious effect of Red 40 on the behavior of most children,” says L. Eugene Arnold, MD, a professor of psychiatry and behavioral health at the Ohio State University, who has conducted research on this topic.

Trials in Britain have linked juices containing dye to a small but significant rise in hyperactivity in children, with or without ADHD.

A review of 27 studies looking at artificial dyes, including Red 40, concluded that evidence “supports a relationship between food dye exposure and adverse behavioral outcomes in children.”

Allergic Reactions

According to Dr. Arnold, research has identified three genes that may direct the body’s reaction to synthetic dyes. One gene is involved in the synthesis of dopamine, a molecule that promotes focus and impulse control; the two other genes are involved in the synthesis of histamine, a molecule that promotes alertness.

Too much histamine, however, can bring on allergy symptoms.

The Center for Science in the Public Interest says that Red 40 may trigger allergic reactions in some people, causing hives and facial swelling.

Cancer

“Red Dye 40 is generally considered safer than the now-banned Red Dye 3, since it has not been shown to cause cancer in animals like Red 3 did with thyroid tumors,” says Lorne Hofseth, PhD, an associate dean for research with the Drug Discovery and Biomedical Sciences College of Pharmacy at the University of South Carolina in Columbia, who has conducted extensive research on artificial dyes.

Still, it’s known that Red 40 can contain trace amounts of benzene and 4-aminobiphenyl, which are known human carcinogens.

“Concerns about Red 40’s potential for accelerating cancer through DNA damage and inflammatory mechanisms suggest it may not be entirely risk-free,” Dr. Hofseth says.

Hofseth explains that synthetic dyes by their nature have the potential to result in inflammation.

“Synthetic food dyes are, by definition, xenobiotic, or foreign to the body,” he says. “Things that are foreign to the body are going to stimulate an inflammatory immune response and cause damage to cells.”

 Long-term inflammation and cancer are “intimately” connected, he says.
Hofseth and his collaborators conducted research on mice injected with the equivalent of an “acceptable” human daily intake of Red 40, and observed a low level of inflammation in the rodents’ colons after nine months.

They also looked at human colon cells exposed to Red 40 and saw DNA damage that increased as the dose of Red 40 increased.

Still, a dearth of research involving human subjects makes it difficult to know if results from animal and cell studies predict real-life cancer risk in people.

“The evidence for a cancer connection is suggestive but not conclusive — animal studies and cell research provide ‘pretty good’ evidence, but robust human studies are still needed to confirm the link,” Hofseth says.

Names for Red Dye 40

Red Dye 40 has a number of different names that may appear on an ingredient list, including:

  • Allura Red AC

  • Red 40 Lake
  • Red 40
  • FD&C Red No. 40
  • FD&C Red No. 40 Aluminum Lake

Common Food and Products That Contain Red Dye 40

Many foods that commonly include Red 40 have the bright color one would associate with the dye:

  • Pastries
  • Cakes and frosting
  • Cereals (such as Froot Loops, Lucky Charms, Trix, Fruity Pebbles)
  • Candy and gum (such as M&Ms, Skittles, Jolly Rancher, Starburst, Bubblicious)
  • Yogurt
  • Puddings
  • Gelatins
  • Ice cream
  • Popsicles
  • Soda and soft drinks (such as Hi-C, Code Red Mountain Dew, and Minute Maid Orange Soda)
  • Sports drinks
  • Energy drinks
  • Protein powders
  • Chips and salty snack foods (such as Nacho Cheese Doritos, Planters Cheez Balls, and Combos Pizzeria Pretzels)

The coloring can also be found in barbecue sauces, bouillon cubes, packaged fruit salads, and certain cereal bars.

Red 40 is not only found in many items that are bright red, but in some products with different colors, such as pickled ginger and wasabi-covered peas.

Certain medications and vitamins also use Red 40 to enhance appearance and provide brand identity. Dyes may be used to associate the visual appearance with the appropriate flavor in products like cherry-flavored children’s cough syrup, for instance.

The synthetic pigment is also found in a range of cosmetics, nail treatment, soaps, and skin care products, including lipstick, eyeliner, eyeshadow, blush, bubble baths, and even some kids’ toothpastes.

How to Limit or Avoid Red Dye 40

The best way to avoid Red Dye 40: “Read the labels of the food products you buy,” says Dr. Arnold. “The FDA requires food manufacturers to list all ingredients on the label, including dyes.”

He suggests that products may be healthier if they have coloring from natural sources, such as beets, turmeric, paprika, matcha, strawberries, and saffron, for example.

Arnold adds that parents may want to steer their children away from foods containing synthetic coloring, especially if they have an anxiety disorder or ADHD.

The Takeaway

  • Red Dye 40 in small amounts is unlikely to harm most people, and the FDA permits it in food and regulates its safe use.
  • Still, some studies indicate that the dye may worsen behavioral issues in some children, and studies involving mice and human cells suggests a potential link to cancer, requiring more research to confirm.
  • To limit intake of Red Dye 40, avoid products containing these artificial pigments by checking product labels.

Resources We Trust

Meet Our Experts
See Our Editorial PolicyMeet Our Health Expert Network
Justin Laube, MD

Justin Laube, MD

Medical Reviewer

Justin Laube, MD, is a board-certified integrative and internal medicine physician, a teacher, and a consultant with extensive expertise in integrative health, medical education, and trauma healing.

He graduated with a bachelor's in biology from the University of Wisconsin and a medical degree from the University of Minnesota Medical School. During medical school, he completed a graduate certificate in integrative therapies and healing practices through the Earl E. Bakken Center for Spirituality & Healing. He completed his three-year residency training in internal medicine at the University of California in Los Angeles on the primary care track and a two-year fellowship in integrative East-West primary care at the UCLA Health Center for East-West Medicine.

He is currently taking a multiyear personal and professional sabbatical to explore the relationship between childhood trauma, disease, and the processes of healing. He is developing a clinical practice for patients with complex trauma, as well as for others going through significant life transitions. He is working on a book distilling the insights from his sabbatical, teaching, and leading retreats on trauma, integrative health, mindfulness, and well-being for health professionals, students, and the community.

Previously, Dr. Laube was an assistant clinical professor at the UCLA Health Center for East-West Medicine and the David Geffen School of Medicine at UCLA, where he provided primary care and integrative East-West medical consultations. As part of the faculty, he completed a medical education fellowship and received a certificate in innovation in curriculum design and evaluation. He was the fellowship director at the Center for East-West Medicine and led courses for physician fellows, residents, and medical students.

See full bio

Don Rauf

Author

Don Rauf has been a freelance health writer for over 12 years and his writing has been featured in HealthDay, CBS News, WebMD, U.S. News & World Report, Mental Floss, United Press International (UPI), Health, and MedicineNet. He was previously a reporter for DailyRx.com where he covered stories related to cardiology, diabetes, lung cancer, prostate cancer, erectile dysfunction, menopause, and allergies. He has interviewed doctors and pharmaceutical representatives in the U.S. and abroad.

He is a prolific writer and has written more than 50 books, including Lost America: Vanished Civilizations, Abandoned Towns, and Roadside Attractions. Rauf lives in Seattle, Washington.

See full bio
See Our Editorial PolicyMeet Our Health Expert Network
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Bailey MM. Synthetic Food Dyes: A Rainbow of Risks. Center for Science in the Public Interest. April 15, 2024.
  2. California Leads the Nation With First an on Six Harmful Food Dyes in School Food. Consumer Reports. September 28, 2024.
  3. Summary of Color Additives for Use in the United States in Foods, Drugs, Cosmetics, and Medical Devices. U.S. Food and Drug Administration. March 4, 2022.
  4. Brasch B et al. RFK Jr. Claims Canadian Froot Loops have 3 Ingredients. They have 17. Washington Post. November 12, 2024.
  5. FDA to Revoke Authorization for the Use of Red No. 3 in Food and Ingested. U.S. Food and Drug Administration. January 15, 2025.
  6. Color Additives History. U.S. Food and Drug Administration. November 3, 2017.
  7. Petroleum Product of the Week: Artificial Food Dye. Petroleum Service Company. September 9, 2016.
  8. Rohrig B. Eating With Your Eyes: The Chemistry of Food Colorings. American Chemical Society. October 2015.
  9. Beyond Red Dye No. 3: Here’s What Parents Should Know About Food Colorings. NPR. January 18, 2025.
  10. Arnold LE et al. Artificial Food Colors and Attention-Deficit/Hyperactivity Symptoms: Conclusions to Dye for. Neurotherapeutics. August 3, 2012.
  11. Bateman B et al. The effects of a double blind, placebo controlled, artificial food colourings and benzoate preservative challenge on hyperactivity in a general population sample of preschool children. Archives of Disease in Childhood. June 2004.
  12. McCann D et al. Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. The Lancet. November 3, 2007.
  13. Miller M et al. Potential impacts of synthetic food dyes on activity and attention in children: a review of the human and animal evidence. Environmental Health. April 29, 2022.
  14. Red Dye 3: FDA Finally Bans Cancer-Causing Food Dye. Center for Science in the Public Interest. January 15, 2025.
  15. Kobylewski S et al. Toxicology of Food Dyes. International Journal of Occupational Environmental Health. July-September 2012.
  16. Is Red Dye 40 Safe? Cleveland Clinic. March 8, 2023.
  17. Hofseth L et al. Allura Red AC is a xenobiotic. Is it also a carcinogen? Carcinogenesis. August 12, 2024.
  18. Zhang Q et al. The Synthetic Food Dye, Red 40, Causes DNA Damage, causes colonic inflammation, and impacts the microbiome in mice. Toxicology Reports. September 6, 2023.
  19. Allura Red. International Association of Color Manufacturers.
  20. Welcome to Red40. Red40.
  21. Persellin K. Surprise! Foods you’d never guess contain artificial food dye. Environmental Working Group. July 31, 2024.
  22. Lehmkuhler AL et al. Certified food dyes in over the counter medicines and supplements marketed for children and pregnant women. Food and Chemical Toxicology. September 2020.
  23. Products Containing FD&C Red No. 40 (Ci 16035). Environmental Working Group.
  24. Color Additives Questions and Answers for Consumers. U.S. Food and Drug Administration. December 14, 2023.