Is Soap Residue Harmful? Why Human-Safe Ingredients Matter

By Marilee Nelson | 07/09/2025

Just like laundry, the dishes are never-ending. You scrub, rinse, and load the dishwasher every day, expecting clean dishes in return.

But what if that “clean” plate isn’t actually clean?

Even after a thorough wash with conventional dish soap and warm water, residue can linger on plates, cups, and silverware, often without you knowing. This invisible or cloudy film leaves behind harmful chemicals that end up in your food and, eventually, in your body.

So, you might be wondering: “Is soap residue on dishes harmful?” It’s a good question, and one worth answering.

In this article, we will explore what soap residue is, how it forms, and how to avoid it. Let’s dive in!

Understanding Soap Residue on Dishes

Soap residue is the thin, cloudy, or invisible film left behind on dishes after washing.

There are several ways soap residue can form on dishes:

Hard water and minerals interacting with dish detergent
Using too much or the wrong type of detergent
Not rinsing dishes well
Stuck-on food particles reacting with detergent

If soap residue is left on your dishes or cups, there’s only one place it’s going–on your food and, eventually, in your body.

Residue from automatic dishwashing detergents (ADDs) and hand-washing soaps, however, isn’t the same.

ADDs are formulated with strong alkalis, corrosion inhibitors, and enzymes to break down food particles. They also contain synthetic fragrances to mask food odors and foam suppressors to minimize suds.

On the other hand, hand-washing soaps are generally much milder because they are designed for direct contact with your skin.

Learn more in Why Human-Safe Dishwashing Is So Important.

The Health Risks of Ingesting Soap Residue

Ingesting soap residue, specifically from ADDs, is harmful because of the concentrated nature of the caustic chemicals. In fact, dishwasher detergents are a leading cause of childhood poisoning in the United States.[1]

Many conventional dish soaps contain ingredients that are rated poorly by the Environmental Working Group (EWG).

In fact, the EWG gave an F rating to 14% of the 143 dishwasher detergents it reviewed, nothing their ingredients are of “high concern” and are considered most harmful.

Nearly 36% of all dishwasher detergents received either a D or an F. [2]

To create ADDs, a high alkalinity level of 10 or higher is required, with liquid options reaching an astounding 13. This level of alkalinity gives ADDs their corrosive abilities to remove food, grease, and grime. Hence how and why residue left behind on dishes is extremely harmful to humans and even pets.

According to Poison Control, if ADDs are ingested, they “can irritate the mouth, throat, and stomach, resulting in a bad taste, burning throat, nausea, or vomiting. Swallowing an ADD can also result in extreme outcomes, such as severe burns and swelling of the throat, esophagus (food pipe), and stomach. Someone might also choke when swallowing an ADD, causing some to slip into the airway, resulting in coughing, chest pain, wheezing, and shortness of breath.” [3]

Yet, there are no national requirements for cleaning product labels to disclose the ingredients used in ADDs and dish soaps.

To make matters worse, most of us have never been warned about the potential dangers of using these products in our homes.

While acute poisoning is rare, chronic low-level exposure may have cumulative effects including digestive system issues, allergic reactions and sensitivities, and endocrine disruption.

Digestive System Issues

Ingesting soap residue can irritate the gastrointestinal tract, causing symptoms like nausea, vomiting, diarrhea, and abdominal pain.

Over time, residue buildup in the digestive system can irritate and damage the lining of the stomach and intestines.

A 2023 study found that ingesting dishwasher soap can severely damage the gut’s epithelial barrier and cause significant inflammation. The culprit? Alcohol ethoxylates found in rinse aid components. [4]

Allergic Reactions and Sensitivities

Conventional dish soaps often contain an extensive list of synthetic chemicals designed to break down food, grease, and grime, leaving dishes shiny and “clean.”

However, many of these ingredients can trigger allergic reactions and sensitivities.

An allergic reaction occurs when the immune system senses an attack and releases an antibody called immunoglobulin E (IgE). For those sensitive to dishwashing detergent, exposure can trigger immediate symptoms such as skin redness, itching, burning, sneezing, wheezing, or even difficulty breathing.

Common allergens found in dish soaps include:

Alcohol: Frequently used in conventional dish soaps, alcohol can strip away natural oils and lead to skin dryness and irritation.
Fragrances: A leading cause of contact dermatitis, synthetic fragrances are often found in conventional dish soaps and ADDs. They can also trigger respiratory allergies, especially in sensitive individuals.
Sodium lauryl sulfate (SLS): A foaming agent in dish soap known to irritate sensitive skin.
Synthetic preservatives: Added to extend shelf life, synthetic preservatives like parabens, formaldehyde, and methylisothiazolinone have been linked to skin sensitivities and allergic reactions.

Endocrine Disruption

Endocrine-disrupting chemicals are synthetic or natural substances that mimic human hormones.

When these chemicals come into contact with your skin regularly, are inhaled, or ingested, they cause an imbalance of hormones, like estrogen, which can lead to various unwanted symptoms of hormonal imbalance or “estrogen dominance” in all genders.

This can also affect growth, development, and reproductive function in young children. [5]

Individuals with hormonal issues such as endometriosis, PMS, PCOS, mood swings, fertility issues, menopause, or other hormonal imbalances should especially avoid endocrine-disrupting chemicals at all costs, as they can exacerbate the issue further.

Some common endocrine-disrupting ingredients to avoid include:

Fragrances: Including those scented with “natural fragrances” or even some essential oils. [6]
Synthetic surfactants such as SLS, SLES, and others create endocrine disruptors, like 1,4-Dioxane, which is also a carcinogen.

Read more about Endocrine Disruptors in Cleaning Products and how to avoid them.

Most Concerning Ingredients In Dish Soaps

Now that you know that conventional dish soaps are full of potentially harmful chemicals, let’s look at some specific ingredients to watch out for.

The ingredients in conventional dish soaps that pose the greatest potential health risks include:

Fragrances: Synthetic fragrances create a “pleasant” scent, but often contain a cocktail of harmful synthetic chemicals, including phthalates, formaldehyde, benzene derivatives, and many more. Fragrances are known to cause respiratory irritation, hormone disruption, migraines and headaches, skin sensitization, and more.
Dyes: Typically made with benzidine, a known carcinogen, dyes have been linked to mood disorders, such as hyperactivity. Look for, and avoid, “FD&C Blue” or “Yellow-5” on the label.
Surfactants: The most common are sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES), ammonium lauryl sulfate (ALS), and ammonium laureth sulfate (ALES). These surfactants are the main cleaning agents in conventional dish soap that can cause irritation to the skin, eyes, and mucous membranes.
1,4-dioxane: A byproduct of ethoxylation, this harmful ingredient is an inexpensive shortcut manufacturers use to produce softer, sudsier dish soaps and make detergent chemicals less harsh. It’s known to cause kidney and liver damage, irritation of eyes and nose, contains cancer-causing properties, and is on California’s Prop 65 List. [7]
Formaldehyde: Ingesting formaldehyde has resulted in corrosion of the gastrointestinal tract and inflammation and ulceration of the mouth, esophagus, and stomach.
Phthalates: Endocrine-disrupting chemicals that have been linked to metabolic syndrome, pre-diabetes, cancer, obesity, cardiovascular disease, and systemic inflammation, among others.
Phosphates: Used as surfactants, degreasers, emulsifiers, and water softeners. Exposure has been linked to skin and respiratory irritation, asthma, and many other harmful effects. [Sources 8, 9]
Microplastics: Dishwasher pods are made with a plastic film that is supposed to dissolve during the wash cycle. But this isn’t always the case. These tiny plastic particles can stick to soap residue and enter the bloodstream when consumed.

Safer Alternatives to Conventional Dish Soaps

As you can see, soap residue on dishes can be harmful, especially when conventional dish soaps, or ADDs are used.

If you’re looking to reduce your exposure to harmful chemicals, there are safer alternatives that are both earth-friendly and human-safe.

At Branch Basics, we offer gentle, safe, plant- and mineral-based formulas that effectively clean your dishes without leaving behind harmful residues.

Or, if you prefer a DIY option, simple ingredients like vinegar, baking soda, and liquid castile soap can also get the job done.

Branch Basics

Branch Basics’ all-in-one cleaning system is a much safer alternative to conventional dish soaps.

We have two options available:

For the Dishwasher: Branch Basics Dishwasher Tablets

Our Dishwasher Tablets were inspired by the human-safe ingredients in the Concentrate and Oxygen Boost to provide a superior clean without harmful synthetic chemicals.

They are free of any synthetic fragrance, sulfates, formaldehyde, dyes, ethoxylates, chlorine, phosphates, phthalates, and plastic film.

These small, but mighty, tablets were formulated with powerful plant, mineral, and enzyme-based cleaners, are EWG-verified, Leaping Bunny Certified, and are super affordable at $0.38-$0.34 per load.

For Hand Washing Dishes: Branch Basics Concentrate

For handwashing dishes, the Branch Basics Concentrate is a human-safe, effective and sustainable option. It’s made from our plant- and mineral-based formula, created with the most sensitive in mind. The Concentrate is gentle on your skin, yet cuts through stuck-on food and grease on dishes.

To use undiluted, add 1 teaspoon of Concentrate to a sink full of hot water and hand wash. Rinse well, then dry.

You can also make our Foaming Wash – made by diluting Concentrate in water – and use it as a safe, efficient, and convenient way to hand wash dishes.

Either squirt directly onto the dishes and scrub, or add a few pumps to a sinkful of warm water, agitate to create foam, and wash. Rinse well and dry.

DIY Dish Cleaning Solutions

Making your own dish soap is a safe, natural, and healthy alternative to conventional products.

With just a few ingredients from your pantry, you can create your own DIY dish cleaning solutions that are free from harmful chemicals and gentle on your skin.

DIY Castile Soap Dish Cleaning Solution

Ingredients:

1 cup liquid Castile soap
1 tablespoon washing soda (also known as sodium carbonate)
¼ cup warm water

Instructions:

Heat the water (don’t boil). Add the washing soda and stir until dissolved.
In a separate bowl, combine the liquid Castile soap with the washing soda solution.
Mix well.
Pour into a storage container or soap dispenser.
Shake gently before each use.

How to Test for Soap Residue on Your Dishes

After washing and drying, you may be wondering if your dishes are truly residue-free. Even though they appear clean, soap residue may still be present.

Here are a few simple ways to test for soap residue on your dishes:

Visual Inspection

Give your dishes a thorough look-over. Check for cloudiness or a white film in areas where soap tends to get trapped. Look under the rims of cups, in the corners of bakeware, pots, and pans, and on the silverware handles.

Do a Squeak Test

“Squeaky clean” takes on a whole new meaning when testing for soap residue on dishes.

Here’s how to do it:

After washing and rinsing your dishes, let them dry completely. Run your finger across the dishes’ surface. If it squeaks, the dish is clean and residue-free. If it doesn't squeak or feels slippery, chances are soap residue is still present.

Safer Dishwashing with Branch Basics

Ready to simplify your dishwashing routine?

Branch Basics Dishwasher Tablets replace conventional ADDs, providing truly clean dishes without harmful synthetic chemicals like the ones listed in this article. They are free of any fragrance, sulfates, formaldehyde, dyes, ethoxylates, chlorine, phosphates, phthalates, and plastic.

Or, our all-in-one Concentrate is a great option for handwashing dishes. Check out our Premium Starter Kits (available in refillable plastic or glass), which contain everything you need to make your own human-safe cleaning products, dish soap, laundry products, and more.

For more on natural and human-safe dishwashing, check out:

References:

Marilee Nelson

Marilee Nelson is an Environmental Toxins expert who has spent nearly 30 years advocating for the chemically-sensitive and chronically-ill. She is a Board Certified Nutritionist, Certified Bau-Biologist and Bau-Biology Inspector and specializes in Food As Medicine. She has helped thousands of families and individuals identify, heal and recover from toxic exposures and is on a mission to revolutionize the way American families view their health.

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