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Once considered the domain of Mr. Bubbles and Calgon, bath bombs and fizzies are a current trend to turn the functional bath into a sensory experience. These products offer a tingling effervescence, a kaleidoscope of colors, and a host of mood-enhancing aromas right in your bathtub. These popular fizzing bath-time products are enjoyed by kids and adults.
Bath bombs and bath fizzies are very similar. These products are available in granules (fizzy) or, more commonly, hard-packed dry ingredients (bomb). The most common bath bombs are spherical, but they are also available in a variety of other shapes such as flowers, sea shells, and even bakery items. Many cupcake- and donut-shaped bath bombs look good enough to eat, so it should be no surprise when a toddler takes a bite.
The ingredients that make these bath products fizz are sodium bicarbonate and citric acid. Sodium bicarbonate is also known as baking soda. Citric acid is a weak acid found in citrus fruits. When these dry ingredients dissolve in water, they react and lots of carbon dioxide bubbles are released over several minutes as the bath bomb breaks apart. This effervescence is similar to what is seen when an Alka-Seltzer tablet is dropped into a glass of water. Other ingredients that might be included are soaps, oils, butters, mineral salts, fragrances, dyes, flower petals, and glitter.
Some companies suggest that their bath bombs have detoxifying properties or provide other health benefits such as pain relief, but there is little evidence to back these claims. Some bath bombs include the mineral salt magnesium sulfate, commonly known as Epsom salt. For years, soaking in a tub with Epsom salt has been promoted as a way to increase magnesium in the body, which would relieve a variety of ailments such as sore muscles, cramps, and stress. While there are anecdotal reports of health benefits, the claims are not backed by good science. Magnesium is not well absorbed through the skin, so there are no internal benefits from the magnesium salt in the bath water. Any relief of muscle soreness is probably just from the warm water. So don't believe the hype, just enjoy the bath.
Products with ingredients such as cocoa butter and almond oil can provide temporary relief of dry skin. These kinds of moisturizers are also found in traditional bath oils and body lotions. In addition to the fizzing ingredients, the fragrances, dyes, botanicals, and glitter are simply intended to enhance the bathing experience. There are several recipes for homemade bath bombs that contain many of the same ingredients found in commercially prepared products.
When used as directed, bath bombs are generally safe. The main concern is skin sensitivity to some of the ingredients such as fragrances and dyes. Even "natural" fragrances obtained from plants, such as limonene and linalool, are known to cause allergic dermatitis. People with sensitive skin probably should not use bath bombs. Not all products recommend rinsing off the skin after using, but this is a good idea to remove residual chemicals or glitter from sensitive places. The bathtub will benefit from a cleaning as well, although your plumber might object to rinsing solid material, such as flower petals, down the drain.
Unintentionally swallowing a small amount of bath water with a dissolved bath bomb should not be dangerous because the ingredients would be very dilute. Similarly, contact between the bath water and the eyes should also be well tolerated. Direct contact of the granules or powder with the eyes can produce irritation that should resolve after a thorough rinsing with water.
The bright colors and food shapes of many bath bombs can be attractive to toddlers, so unintentional ingestions should be expected. The most toxic ingredient of these products is the sodium. Sodium, also found in table salt, can cause dangerous body-wide effects such as confusion, coma, and muscle weakness in excessive amounts. While a toxic dose of sodium is known, most commercially available products do not list the sodium composition, so a toxic amount of a product is hard to determine. It is reasonable to assume that a toddler ingesting a taste amount, a lick, or a few small granules would not swallow enough to cause concerning body-wide effects. The other ingredients are less toxic, so they would take a much larger amount ingested to be a problem. Some of the ingredients can be irritating to the mouth and stomach, so nausea and vomiting are possible. Products containing magnesium sulfate can cause diarrhea. Many of the ingredients would be considered non-toxic such as flower petals and glitter. The symptoms resulting from swallowing small amounts of these bath products should be mild and usually can be managed at home. Ingestions of larger amounts have the potential to cause serious effects and medical management at a healthcare facility might be needed.
Treatment for ingestion of any of these products is rinsing out the mouth and drinking a few sips of water to clear the mouth and throat. Mild vomiting and diarrhea can be managed at home by slowly sipping water to stay hydrated. Eye exposures should immediately receive a 15-minute irrigation with room temperature water.
Anyone having effects such as severe abdominal pain, persistent diarrhea, weakness, agitation, confusion, or seizures should seek medical evaluation right away. Medical evaluation is also needed for any eye exposures that have ongoing effects such as eye pain or sensitivity to light that does not resolve an hour or so after irrigating the eye.
If you suspect someone has ingested bath fizzies or bath bombs, have them rinse out their mouth and drink a few sips of water. Then check the webPOISONCONTROL® online tool for further guidance or call Poison Control at 1-800-222-1222.
Audrain H, Kenward C, Lovell CR, Green C, Ormerod AD, Sansom J, et al. Allergy to oxidized limonene and linalool is frequent in the U.K. Br J Dermatol. 2014 Aug;171(2):292-7.
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Gröber U, Werner T, Vormann J, Kisters K. Myth or reality-transdermal magnesium? Nutrients 2017 Jul 28;9(8):E813.