When you tear open a pack of rainbow candy or sip on a neon-blue sports drink, you're getting more than just sugar and flavor. Those bright, bold colors come from artificial food dyes (lab-made chemicals added to give foods their color), and they've been in our food for over 100 years. These synthetic colors show up in about one in five packaged foods and drinks sold in the U.S. today, but their story is far more complicated than most people realize.

A Purple Mistake That Started It All

Back in 1856, an 18-year-old British chemist named William Henry Perkin was trying to make synthetic quinine (a drug used to treat malaria). Instead, he accidentally created the first artificial dye: a brilliant purple compound called mauve. He tested it on fabric and was amazed by how vivid the color looked on silk. Even Queen Victoria wore dresses dyed with Perkin's creation. That lucky mistake kicked off the "coal-tar dye" era, named for the fact that early dyes were made from coal tar, a thick, tar-like substance left over from the production of fuel.

By 1900, adding artificial dyes to food, drugs, and cosmetics had become normal. But there was a dark side. Many of these dyes contained dangerous substances like lead, mercury, and arsenic. Imagine walking into a bakery in the 1890s and buying pickles made bright green with lead chromate or bread that looked fresher thanks to copper sulfate. These weren't isolated incidents, and people got sick as a result.

Eventually, enough harm had been done that the U.S. government stepped in. The 1906 Pure Food and Drugs Act (also called the Wiley Act) was the first federal law to crack down on unsafe food additives. This law laid the groundwork for what would eventually become the FDA. By 1907, only seven dyes were allowed in food, and even those got reevaluated over time. Today, the FDA certifies just nine synthetic dyes for food use.

What These Dyes Are Made From Today

The food dyes we use now are a far cry from the old coal-tar concoctions, though they still come from petroleum (crude oil used to make gasoline and plastics). That might sound disturbing, but the final dye bears no resemblance to raw crude oil. As I've mentioned before, it's all about the chemistry. The process involves selecting chemicals and combining them in controlled reactions to make color compounds. These are then purified to remove byproducts and dried into stable powders or liquids.

The most common dyes are Red 40, Yellow 5, Yellow 6, Blue 1, Blue 2, Green 3, Red 3, Orange B, and Citrus Red 2. Each one has a specific chemical makeup and function. If you've eaten a cherry-flavored candy in the U.S., chances are you've consumed Red 40, the most used dye in the country.

Chances are you've also consumed all sorts of other things, by the way. Environmental contaminants often find their way into our food, and there is little we can do about it. They're hard to regulate, too. After all, you can't keep plants from the air or water, and contaminants are in those. The best we can do is test food and identify extreme contamination at levels that are not safe. The same applies for food dyes.

Where These Dyes Show Up in Food

These artificial colors are everywhere. A study of nearly 40,000 packaged foods found synthetic dyes in about 19% of them. That's where the "one in every five" number comes from when we talk about which items you toss into your shopping cart with dyes in them. And in products marketed to kids — like candy, breakfast cereals, and ready-made meals — these dyes show up even more often.

Some of this is obvious. Neon-colored drinks and rainbow cereals practically shout, "I contain dyes!" But artificial colors also sneak into surprising places: white frostings (to make them appear whiter), yogurts, applesauce, some meats, marshmallows, and even seasoning blends.

Let's imagine a fictional example. Sarah packs lunch for her daughter Emma: a turkey sandwich, apple slices, yogurt, and fruit snacks. Seems pretty healthy. But the turkey may have Red 40 to enhance its pink color. The yogurt could have Red 40 and Blue 1 to achieve a perfect strawberry hue. And those "natural" fruit snacks? They might still use artificial colors despite what the label suggests.

Some categories use synthetic dyes more than others. Sports drinks top the list — about 79% use them. Even companies with health-focused branding sometimes use these dyes, although consumer pushback is beginning to change that.

What the Research Says About Health Effects, Like Behavioral Issues in Children

This is where things get complicated. The effects of synthetic dyes vary depending on the specific dye, the amount consumed, and the person consuming it. But let's break down some of the most discussed concerns.

One of the longest-standing debates is whether food dyes have an impact on children's behavior. In the 1970s, Dr. Benjamin Feingold noticed that some of his young patients became calmer when artificial dyes were removed from their diets.

More recently, a 2021 report from California's Office of Environmental Health Hazard Assessment looked at decades of research and found that synthetic dyes can lead to hyperactivity and other behavioral issues in some children. In many of these studies, kids were given dye-free diets for a while and then reintroduced to foods with dyes.

About two-thirds of those studies showed a connection between dye intake and behavior changes. That doesn't mean all kids react this way, but some definitely do. Animal studies back this up, showing that synthetic dyes can affect learning and memory, alter brain chemistry, and even cause structural brain changes in lab animals.

What About Allergic Reactions or Cancer Worries?

Some people are allergic to food dyes, though the allergy is not very common. The most well-known offender is Yellow 5 (Tartrazine), which can trigger asthma, hives, or even a severe allergic reaction called anaphylaxis in sensitive people. Red 40 and Yellow 6 have also been associated with rashes and breathing difficulties.

Additionally, the link between artificial dyes and cancer is less clear; however, one dye in particular (Red 3) has raised concerns. Back in the 1980s, researchers discovered that Red 3 could cause thyroid tumors in male rats. Although it was eventually banned from cosmetics and topical medicines, surprisingly, it remained legal in food products. That's starting to change. In January 2025, the FDA announced a phased ban on Red 3 in foods and medicines, which will be fully implemented between 2027 and 2028.

Newer studies suggest Red 40 may also be a cause for concern. In one 2023 experiment, mice fed Red 40 along with a high-fat diet had more inflammation and DNA damage in their colons. The scientists were curious if this could shed some light on why colorectal cancer rates are increasing among young adults. Still, it's worth noting that these animal studies often use very high doses of dye, much more than people usually eat. Of course, we need more research involving people to truly understand it.

How Much Is Too Much?

The FDA sets Acceptable Daily Intake (ADI) levels for each approved dye. For example, Red 40's ADI is 3.2 milligrams per pound of body weight. That means a 150-pound person could consume up to 476 milligrams per day without expected harm. Most Americans eat well below that amount.

But there's a catch: the safety studies the ADI levels are based on were mostly done decades ago and weren't designed to pick up on behavioral changes in kids. California's 2021 review suggests the current limits might not do enough to protect more sensitive populations. That is, the science on ADI is not settled, and more research is needed, even if the dyes are banned from food.

So Why Do Food Companies Still Use These Dyes?

If artificial dyes come with risks, why are they still used so much? It mostly comes down to appearance, practicality, and cost.

Color plays a role in how we experience food. We expect red to mean cherry, orange to mean citrus, and green to suggest lime or apple. If a product's color doesn't match its flavor, it can seem "off," even if the taste is the same. Synthetic dyes help manufacturers deliver bold, consistent colors that match customer expectations every time.

They also have practical advantages. Artificial dyes are stable. They don't fade when heated, exposed to light, or stored over time. They're intense, so a little goes a long way. They're cheap, and they usually don't affect the taste of food. Natural dyes, by contrast, can be more expensive, more likely to change flavor, and less consistent.

Changes Are Coming

Despite their advantages, synthetic dyes are likely to become much less common. In April 2025, the U.S. Department of Health and Human Services announced a plan to phase out all petroleum-based dyes by the end of 2026. The policy includes an immediate halt on the use of Citrus Red 2 and Orange B and a timeline to eliminate the six most widely used dyes (Red 40, Yellow 5, Yellow 6, Blue 1, Blue 2, and Green 3). The agency is also fast-tracking approvals for safer, natural alternatives.

Several states are taking their own steps. California banned Red 3 from foods in 2023. Texas now requires warning labels on products with synthetic dyes (though there are some inaccuracies in its enforcement). In the European Union, foods containing certain artificial dyes must carry labels warning that they may affect children's behavior.

What to Take Away from All This

So, where does that leave you as a consumer? For most people, synthetic food dyes are generally considered safe when eaten in small amounts. But there are exceptions. Some kids respond with hyperactivity. Some individuals have allergic reactions. A few dyes have raised concerns about cancer, at least in animal studies.

If you're a parent, and your child seems to bounce off the walls after eating bright-colored foods, it might be worth trying a dye-free diet for a few weeks to see if it makes a difference. If you have allergies or asthma, be cautious about products containing Yellow 5, Red 40, or Yellow 6.

And even if you're not worried about dyes themselves, it's worth noting that the foods containing them often aren't the most nutritious. Research shows that foods with artificial colors tend to have more sugar and fewer nutrients.

The big picture here isn't just about color. The message should be about what our food is made of, how it's marketed, and what we want to put into our bodies. Synthetic dyes are a vivid example of how science, policy, and public opinion interact in the things we eat every day.

Whether you prefer to steer clear of them entirely or simply don't give it much thought, knowing where food dyes come from, what they do, and how they're regulated can really help you make informed choices. That's what good public health is all about: understanding the facts so you can decide what's best for you and your loved ones.