Updated on September 15, 2020


Created on September 15, 2020

Surprise Soap

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Surprise Soap is a soap bar with a surprise in the middle to encourage children to wash their hands.

Developed By Unknown
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Product Description

Surprise Soap is a soap bar that has a toy embedded in the middle of the soap bar to encourage children to wash their hands. Surprise Soap was made specifically for a pilot hygiene study in Iraq. As of 2020, the researchers are currently setting up two larger trials to test the soaps in Sudan and Somalia and exploring different manufacturing options and pre-existing suppliers.

Distributors / Implementing Organizations

London School of Hygiene & Tropical Medicine

Manufacturing/Building Method

Toys are 3D printed then embedded inside melted local shop-bought soap that is then poured into molds.

Intellectural Property Type

Open Source

User Provision Model

As of 2020, the soap is distributed by the researchers.

Distributions to Date Status




Number of uses


Power supply type




Design Specifications

Toys are co-designed by children and then these toys are embedded inside soap.

Technical Support


Replacement Components



Varies depending on the size of the bar of soap.

Manufacturer Specified Performance Parameters

Increase children's handwashing consistency.

Vetted Performance Status

Through testing in a refugee camp, the study found that with surprise soap 97% of households had utilized the product over the evaluated timeframe. A comparative study based on two control groups that showed the group that has surprise soap washed their hands 4x more.


There are no known safety issues with this product.

Complementary Technical Systems


Academic Research and References

Watson, J., Dreibelbis, R., Aunger, R., Deola, C., King, K., Long, S., Chase, R.P., Cumming., O., 2018,¬†Child’s play: Harnessing play and curiosity motives to improve child handwashing in a humanitarian setting. International Journal of Hygiene and Environmental Health.

Compliance with regulations


Other Information


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