A kids' bath bomb is mostly baking soda and citric acid — the two ingredients that fizz — plus a softening oil, gentle colour and a light fragrance. Here's a plain-English breakdown of what each part does and what to avoid.
The core ingredients
Baking soda (sodium bicarbonate)
The base of every bath bomb. On its own it's a mild water softener; combined with citric acid it creates the fizz.
Citric acid
A natural acid (the stuff that makes citrus tart). When it meets water and baking soda, it reacts to release carbon dioxide — those are the fizzing bubbles.
A carrier oil or butter
Ingredients like coconut oil or shea butter soften the water and help condition skin, so kids step out feeling smooth rather than dried out.
Colour
Good kids' bombs use skin-safe, water-soluble colourants that tint the water for fun and then rinse away cleanly without staining skin or the tub.
Fragrance
A light scent makes the experience nicer. For children, less is more — a subtle fragrance is gentler than a heavy perfume.
What about the surprise toy?
In our Kids Bath Bombs, a small toy is sealed inside and revealed as the bomb dissolves — the bit kids get most excited about. Because the toys are small, the bombs are best for ages 3+ with supervision.
Ingredients to avoid for kids
- SLS / SLES (sulfates): harsh foaming detergents that can dry and irritate.
- Heavy synthetic dyes: can stain and occasionally irritate.
- Strong synthetic fragrance: a common trigger for sensitive skin.
- Glitter (non-biodegradable): messy and not eco-friendly.
How to read a label quickly
Scan for a short ingredient list, “sulfate-free,” gentle or low fragrance, and skin-safe colourants. A clean, simple formula is almost always the better choice for children.
See what goes into our kid-safe bath bombs →
Frequently asked questions
What are bath bombs made of?
The two essential ingredients are baking soda and citric acid, which fizz together in water. Most also contain a softening oil, a skin-safe colour and a light fragrance.
Why do bath bombs fizz?
Citric acid reacts with baking soda once they dissolve in water, releasing carbon dioxide gas — the bubbles you see fizzing to the surface.
Are bath bomb ingredients natural?
The core ingredients (baking soda, citric acid, plant oils) are naturally derived. Colour and fragrance vary by brand, so check the label if natural ingredients matter to you.