Chamomile Bath Salts Recipe: Disperse the Oil First

The usual chamomile bath salts recipe is a cup of Epsom salt, a few drops of oil, stir, jar. It looks finished, and the oil step is where it goes wrong: the Tisserand Institute lists Epsom salt among the things that do not disperse essential oil. This page shows a version with the dispersal step built in, worked out on paper from the cited guidance. We have not made or tested it, and we do not sell salts, jars or dispersants.

Roman Chamomile Essential Oil bottle

Roman Chamomile Essential Oil

Our own Roman Chamomile Essential Oil, in sizes from 0.5 oz to bulk.

From $32.99

Shop Now →

What salt does and does not do for the oil

The Tisserand Institute's bath safety page says that epsom or regular salt, baking soda, cornstarch, glycerin, witch hazel and aloe vera are not recommended for baths as ways of dispersing essential oil. Its reasoning for the whole group is that essential oils are not water soluble, so they float on top of the bath and can sting on warm skin. Reasoning from that, dripping oil onto salt crystals gives you oily salt: when it dissolves, the crystals go into the water and the oil floats off as a film again. Salt is a fine bath ingredient. It is not a carrier for oil.

Tisserand's list of workable dispersants includes polysorbate 20 (mixed with the oil first, using an equal amount, 5 to 20 drops each) and a tapioca-starch product called Natrasorb Bath (5 to 20 drops stirred into half a cup, then added to the bath, with epsom salts optional). The same page says polysorbate 20 and Solubol are different products and are used differently. So the order of operations is: oil into dispersant, dispersant into salt, then salt into the bath.

Is the magnesium the point?

If you want Epsom salt for the magnesium, read the evidence first. Gröber, Werner, Vormann and Kisters reviewed the literature on transdermal magnesium in Nutrients in 2017 and concluded that the claim that skin absorption beats oral intake, with fewer side effects, is not backed by the evidence; they call the propagation of transdermal magnesium "scientifically unsupported". Marketing of sprays, flakes and salt baths is what prompted the review. A 2025 randomised trial of 104 people with cancer ran Epsom salt foot baths against controls for chemotherapy-related nerve symptoms and reported better neuropathy grades in the foot bath group. It did not measure magnesium absorption, so it cannot settle the transdermal question, and its population is not the average reader of this page (the PubMed record is 40510964; we read the abstract only). Our view: buy Epsom salt because you like a salt bath, not because of what it does to your magnesium level. If you have a kidney condition or take medication, your physician or pharmacist is the person to ask about magnesium.

The recipe, in arithmetic first

Every figure here is a calculation from the Tisserand guidance and from our product page's 0.5% to 2% skin range, not a tested ratio. For drop counts we use 20 drops per ml, which is what the German oil page's "3 to 12 drops per ounce" implies at 0.5% to 2% of a 30 ml ounce. Your bottle's drop size may differ.

  1. Pick the dose per bath. Tisserand's range for a dispersant is 5 to 20 drops of oil. We would use the bottom of it, 5 drops per bath, which is 0.25 ml. Reasoning: if the portion's dispersant and oil together are about a tablespoon (15 ml), our page's 2% skin ceiling is 0.3 ml, or 6 drops, so 5 drops stays under it. That is our own reading of two documents that were not written for this use.
  2. Pick the batch size. Say four baths. That is 20 drops of oil (1 ml).
  3. Pre-mix the dispersant. Equal amounts: 20 drops of polysorbate 20 stirred into the 20 drops of oil until it looks uniform. Dispensing the two from separate droppers keeps the drop count honest.
  4. Add the blend to the salt. Stir the 40 drops into a quantity of Epsom salt you choose, say two cups, and mix thoroughly so the liquid does not pool. The salt quantity affects texture and not dose.
  5. Divide into four portions. Each portion is one bath's worth. Use the same scoop every time, because the dose is set by the scoop, not by eye. If you make the batch for ten baths, every number scales: 50 drops of oil, 50 of polysorbate, one tenth of the salt per bath.

The ten-bath check: 50 drops is 2.5 ml. Divided by ten baths it is 0.25 ml each, the same dose. The ratio of oil to salt does not matter for the dose; it only matters that the portions are equal.

What we would leave out and why

Storage and the limits of what we know

Our product page states a typical shelf life of 2 to 3 years for the oil in its sealed, capped bottle, stored cool and dark. We have no shelf life for a salt blend, and we will not invent one. We found no source on how a salt blend ages in a steamy bathroom, so make small batches and keep the jar capped. Label the jar and keep it away from children, since it contains oil and a surfactant and is not food. Never eat it. Our oils are not for internal use.

The oil can stain pale fabric, according to our own Inside the Still page, so rinse the tub after draining and watch the towels. A tub with an oil film is slippery, and we are not citing a study for that; it follows from oil floating on water. Use a mat. A patch test of the dispersed blend, before the first bath, is in the patch test guide.

Who should skip it

Skip it for babies and young children and ask a pediatrician. If you are pregnant or breastfeeding, ask your OB-GYN or midwife first. If you have eczema, open skin or a history of reactions to daisy-family plants (chamomile is one), ask a dermatologist or allergist. Our bath post explains the oil-and-water problem in more depth, the dilution guide covers carrier oil maths, carrier oils compares options, and chamomile essential oil safety collects the cautions.

If you make it, patch test first, mark the jar with the drops per portion, and treat every number above as a starting calculation.

Roman Chamomile Essential Oil bottle

Roman Chamomile Essential Oil

Roman Chamomile Essential Oil from our own shop, in sizes from 0.5 oz to bulk.

From $32.99

Shop Now →

Sources & Further Reading