Elephant toothpaste requires just a handful of common ingredients: hydrogen peroxide, a catalyst (usually dry yeast or potassium iodide), liquid dish soap, and warm water. Food coloring is optional but adds visual flair. The dramatic eruption of foam comes from the rapid decomposition of hydrogen peroxide into water and oxygen gas, with the dish soap trapping that oxygen in millions of tiny bubbles. The recipe is simple, but the concentration of hydrogen peroxide and the choice of catalyst make the difference between a gentle classroom demonstration and the explosive pillar of foam you see in viral videos.
The Core Ingredients and What Each One Does
Every version of elephant toothpaste relies on the same basic chemistry, though the specific products vary depending on how dramatic you want the result. Here is what goes into the mix and why each component matters:
- Hydrogen peroxide: This is the fuel for the reaction. It naturally breaks down into water and oxygen gas, but the process is extremely slow on its own. The higher the concentration, the more oxygen is released and the bigger the eruption.
- A catalyst: Something that speeds up the decomposition of hydrogen peroxide without being consumed in the process. Common choices include dry active yeast dissolved in warm water (for the kid-friendly version) or potassium iodide solution (for the more dramatic version).
- Liquid dish soap: As the oxygen gas rushes out of the hydrogen peroxide, the soap captures it in bubbles. Without soap, you would just get a lot of fizzing liquid. With it, you get that thick, toothpaste-like column of foam.
- Warm water: Used to dissolve the yeast or potassium iodide before adding it to the peroxide mixture. Warm water activates dry yeast more quickly and helps dissolve potassium iodide crystals.
- Food coloring: Purely cosmetic. A few drops mixed into the hydrogen peroxide before the catalyst is added gives the foam a vivid color. Some people swirl multiple colors around the inside of the container for a striped effect.
You also need a container, and the choice matters more than people expect. A narrow-necked bottle or flask concentrates the foam into a tall column. A wide-mouthed container produces a lower, broader eruption. A plastic bottle works fine, and it is safer than glass if you are working with higher concentrations of peroxide.
The Kid-Friendly Version Versus the Full-Scale Demo
The single biggest variable in elephant toothpaste is the concentration of hydrogen peroxide. This is where the “kid-friendly” version and the “science fair showstopper” version diverge sharply, and it is worth understanding the difference before you buy supplies.
The hydrogen peroxide you find at a drugstore is typically 3% concentration, the same stuff used to clean minor cuts. You can use it for elephant toothpaste, and it will produce a respectable mound of foam, but the reaction is gentle and relatively slow. This is the version safe enough for young children to handle with minimal supervision. Some people step up to 6% peroxide, sold at beauty supply stores as a hair-bleaching developer, which roughly doubles the foam output without dramatically increasing risk.
The spectacular eruptions seen on YouTube and in science shows use 30% hydrogen peroxide or higher, sometimes labeled as “food grade” peroxide in concentrated form. At this strength, hydrogen peroxide is a genuine hazard. It causes chemical burns on contact with skin, can bleach clothing instantly, and produces an exothermic reaction, meaning the foam that comes out is hot. This version should only be handled by adults wearing safety goggles, gloves, and ideally a lab coat or long sleeves. It is not a children’s activity at this concentration.
The catalyst choice also shifts between the two versions. Yeast is the standard for kid-friendly demos because it is cheap, safe, and available at any grocery store. About a tablespoon of active dry yeast dissolved in a few tablespoons of warm water does the job. Potassium iodide, typically used with the higher-concentration peroxide, triggers a much faster and more violent decomposition. It is sold as a powder or in solution through chemical supply companies and some online retailers. Manganese dioxide is another catalyst that works well, though it is less commonly available to the general public.
How the Reaction Actually Works
Hydrogen peroxide is an unstable molecule. It “wants” to break apart into water and oxygen, but at room temperature this happens so slowly that a bottle of 3% peroxide can sit in your medicine cabinet for months before it loses potency. The catalyst provides a surface or chemical pathway that lowers the energy barrier for that decomposition, making it happen in seconds instead of months.
When yeast is the catalyst, the active agent is an enzyme called catalase, which is naturally present in living cells. Catalase evolved to protect cells from hydrogen peroxide, a toxic byproduct of normal metabolism. It is remarkably efficient at its job. Research on catalase kinetics has shown that the enzyme’s activity is sensitive to both pH and temperature, with the deactivation rate increasing as pH and temperature rise above optimal ranges.1Catalysts. New Method of Determining Kinetic Parameters for Decomposition of Hydrogen Peroxide by Catalase This is why warm water, not hot water, is recommended for dissolving the yeast. Water that is too hot kills the yeast cells and destroys the catalase before it can work.
When potassium iodide is the catalyst, the mechanism is different. The iodide ion donates an electron to the hydrogen peroxide, which breaks it apart. The iodide is then regenerated in a second step, so it is not consumed and can keep catalyzing the reaction until the peroxide is exhausted. This inorganic catalysis tends to be faster and more complete than the enzymatic route, which is why potassium iodide produces the more explosive results.
In both cases, the oxygen gas released is what creates the foam. A single tablespoon of 30% hydrogen peroxide releases a surprisingly large volume of oxygen. The dish soap traps this gas in a stable foam structure. Without the soap, the oxygen would simply bubble off the surface as a fizzy froth and dissipate immediately.
Why Dish Soap Is Not Optional
People sometimes assume the dish soap is just a minor addition for visual effect, but it is structurally essential to the demonstration. The soap molecules form thin films around the oxygen bubbles, stabilizing them long enough to stack up into the characteristic column of foam. The properties of the soap influence the foam’s texture and longevity. A thicker, more concentrated dish soap tends to produce denser, more stable foam. Watered-down or very cheap soap may produce foam that collapses quickly.
The general physics of foam formation reinforce this. Research on gas-driven foaming processes shows that bubble size, stability, and overall volume expansion depend heavily on the surfactant present and the rate of gas generation.2PubMed Central. Pore topology, volume expansion and pressure development in chemically-induced foam cements In the case of elephant toothpaste, faster gas production (from a stronger catalyst or higher peroxide concentration) creates smaller, more numerous bubbles. Studies on chemically-blown foams have found that lower concentrations of the gas-generating agent produce thicker foam walls with fewer bubbles, while higher concentrations produce finer, more voluminous foam.3PubMed Central. Controlling Morphology and Physio-Chemical Properties of Stimulus-Responsive Polyurethane Foams by Altering Chemical Blowing Agent Content The same principle applies here: more vigorous peroxide decomposition means finer-textured, taller foam.
A squirt of about one to two tablespoons of dish soap is typical for a standard-sized demo. Adding more soap does not necessarily mean more foam, because the limiting factor is the amount of oxygen gas produced, not the amount of surfactant available. Once there is enough soap to coat the bubbles, extra soap just makes the liquid mixture more viscous.
Using Biological Catalysts Instead of Yeast
Yeast works because of its catalase content, but yeast is not the only source of catalase. Almost all living cells produce the enzyme, and some tissues are far richer in it than others. This has made “which biological material makes the best elephant toothpaste” a popular extension of the experiment, particularly in biology classes.
A comparative study testing catalase activity across different tissues found significant variation. Chicken liver extract produced the most vigorous reaction, generating foam heights of roughly 5 to 6 centimeters in a standardized test setup. Beef muscle produced about 3 centimeters. Potato and banana extracts were moderate at around 1.5 to 2 centimeters, and carrot root extract showed almost no visible activity.4International Journal of Science and Research Archive. A comparative analysis of catalase activity in animal and plant tissues collected in Pineville, Rapid Parish, Louisiana, USA The pattern aligns with what you would expect from biology: the liver is the body’s main detoxification organ and handles enormous amounts of hydrogen peroxide as part of normal metabolic processing, so it is packed with catalase. Muscle tissue has less. Plant tissues have even less, though potatoes do contain enough to make a modest demonstration.
If you are doing the experiment with biological materials, blend the tissue with a small amount of water to release the catalase from the cells, then strain it through cheesecloth. A raw liver smoothie is not appetizing, but it makes a surprisingly effective catalyst for elephant toothpaste. This version of the experiment lets students explore enzyme biology in a hands-on way, connecting the chemistry of the foam to the physiology of living organisms.
Safety Considerations That Actually Matter
For the 3% drugstore peroxide version, the main safety concern is mess rather than hazard. The foam is mostly water, oxygen, soap, and food coloring. It is not toxic. It will stain fabric if you used food coloring, and it can be slippery on floors, but there is no meaningful chemical risk. Young children should still be supervised, but this version is genuinely safe for hands-on participation.
The risks scale up sharply with concentration. At 12% and above, hydrogen peroxide causes immediate skin irritation and can bleach or burn skin on contact. At 30%, contact with skin produces painful white patches as the peroxide oxidizes surface tissue. Splashes in the eyes at this concentration are a medical emergency. The reaction itself is exothermic, and the foam produced with 30% peroxide can be warm enough to cause mild burns if a child grabs a handful immediately after the eruption.
A few practical safety points for anyone working with higher concentrations:
- Goggles, not glasses: Safety goggles that seal around the eyes are important. Regular eyeglasses do not protect against splashes from below or the side.
- Gloves: Nitrile or latex gloves protect your hands when pouring the peroxide. Have them on before you open the bottle.
- Ventilation: The reaction releases a large amount of oxygen gas. In a small enclosed space, this is not dangerous in itself, but the vigorous bubbling can aerosolize soap and peroxide droplets. Outdoors is ideal for the big version.
- Container choice: Use plastic, not glass. The reaction can be vigorous enough to knock over a glass flask, and concentrated peroxide plus broken glass is a bad combination.
- No sealed containers: Never cap or seal a bottle containing hydrogen peroxide and a catalyst. The pressure from the released oxygen can cause the container to burst violently.
The foam itself is safe to clean up with water. It does not require any special disposal. Leftover hydrogen peroxide at low concentrations can be poured down the drain. Higher concentrations should be diluted heavily with water first.
Tweaking the Recipe for Bigger or Better Results
Once you have the basic ingredients, several adjustments can change the character of the eruption. The most obvious lever is the amount of hydrogen peroxide. Doubling the volume roughly doubles the foam output, assuming you have enough catalyst to decompose it all. For a standard classroom demo, about half a cup of 3% to 6% peroxide in a 16-ounce bottle works well.
The speed of the reaction depends on how you add the catalyst. Pouring yeast solution in slowly produces a gradual ooze of foam, while dumping it all in at once creates a more sudden burst. With potassium iodide, which reacts almost instantly, the delivery method matters even more. Some demonstrators use a funnel or trough so the catalyst hits the peroxide mixture all at once.
Temperature plays a role as well. Warmer peroxide decomposes faster, so starting with room-temperature or slightly warm peroxide produces a more vigorous reaction than using cold peroxide straight from the refrigerator. However, with concentrated peroxide, the reaction itself generates heat, so pre-warming is unnecessary and can actually make the exothermic reaction harder to control.
The container shape is an underrated factor. A narrow neck forces the foam upward into a dramatic column, which is why Erlenmeyer flasks and soda bottles are popular choices. A wide bowl produces a spreading, lava-like flow that works better for volcano models. Some demonstrators use multiple small bottles arranged in a row and trigger them simultaneously for a cascading effect.
Food coloring technique matters too. Dropping the coloring directly onto the dish soap, which sits on top of the peroxide, rather than mixing it in, creates streaked or marbled foam instead of a uniform color. Using gel food coloring rather than liquid produces more saturated colors because it is more concentrated.
Why Elephant Toothpaste Became a Classroom Staple
Elephant toothpaste has become one of the most widely used chemistry demonstrations in schools, and not just because it looks impressive. The experiment touches on catalysis, decomposition reactions, enzyme biology, and gas laws, all in a format that takes about five minutes and uses inexpensive materials. It scales naturally into inquiry-based learning: students can vary the peroxide concentration, try different catalysts, change the temperature, and measure the foam height to practice experimental design.
Research on the pedagogical impact of the experiment supports this. A study on using elephant toothpaste in middle school science classes found that the majority of students showed positive social-emotional responses, including heightened enthusiasm, collaboration, and curiosity.5Jurnal Pembelajaran, Bimbingan, dan Pengelolaan Pendidikan. PENGARUH PRAKTIKUM ELEPHANT TOOTHPASTE DALAM PEMBELAJARAN GUNUNG BERAPI TERHADAP SOSIAL EMOSIONAL SISWA KELAS 8 SMPN 3 MALANG The hands-on, visually dramatic nature of the experiment engages students who might otherwise tune out a lecture on reaction kinetics. The fact that it can be done safely with low-concentration peroxide makes it accessible even in schools with limited lab facilities.
The experiment also has a natural extension into biology when biological catalysts are used. Comparing the catalase activity of different tissues turns a chemistry demo into a cross-disciplinary investigation, connecting enzyme function to organ physiology. Students often find it surprising that a piece of raw liver can do the same job as packaged yeast, and that insight, that enzymes in their own bodies perform the same chemistry, tends to be memorable.
Where to Buy the Ingredients
For the kid-friendly version, everything is available at a regular grocery store or pharmacy. Hydrogen peroxide at 3% is in the first aid aisle. Active dry yeast is in the baking aisle. Dish soap and food coloring round out the list. Total cost is typically under five dollars if you do not already have these items at home.
For the more dramatic version, hydrogen peroxide at higher concentrations is the ingredient that requires some effort to source. Beauty supply stores carry 6% to 12% developer peroxide, often sold as “20-volume” or “40-volume” cream developer. Concentrations of 30% or higher are sold by chemical supply companies, some pool supply stores (where it is sold for pool sanitation), and certain online retailers. You may need to confirm you are an adult and acknowledge safety information when purchasing.
Potassium iodide can be ordered from chemical supply companies or through Amazon. It is not a controlled substance, but it is not something you will find at a drugstore. A small bottle goes a long way since you only need a few grams dissolved in water per demonstration. Manganese dioxide is similarly available from chemical suppliers and is sometimes found in pottery supply stores, where it is used as a ceramic glaze colorant.
If you are a teacher buying supplies for a class, educational science suppliers like Flinn Scientific and Carolina Biological sell pre-packaged elephant toothpaste kits that include the peroxide, catalyst, soap, and coloring in measured amounts. These kits cost more than sourcing the ingredients separately, but they come with safety data sheets and teacher guides, which can simplify the preparation and satisfy school safety requirements.