Educational information, not medical advice — ask your doctor or midwife.
Acidum muriaticum is a homeopathic remedy made from hydrochloric acid. Its Latin name is Acidum hydrochloricum, and you may also see it sold as hydrochloric acid. Homeopaths have long picked it for deep weakness during a fever, mouth ulcers, and sore haemorrhoids (swollen, painful veins around the back passage).
The starting material is a strong acid that can burn. But you do not take it in that form. It is thinned and shaken over and over again, so at the usual 30C strength almost none of the acid is left in the pill.
Here is the short verdict: careful trials do not show homeopathic remedies working any better than a placebo (a dummy treatment). Acidum muriaticum has a long record inside homeopathy. But long use is not proof that it works, and that point is made here once rather than in every section below.
There is no accepted explanation for how Acidum muriaticum could work. At 30C there is no hydrochloric acid left in the dose to act on your body.
Homeopathy has its own idea, called the "law of similars". It says a substance that causes certain symptoms in a well person can ease the same symptoms in a sick one.
Homeopaths also believe that thinning and shaking the liquid leaves an active imprint behind. Chemistry, body science and trial results do not back up either idea.
Something real does happen, but it is not specific to the remedy. Attention, hope, time, and the way many illnesses fade on their own all shape how you feel after taking anything.
Sugar pillules, which are small round pills, are the most common form. They are sold by strength, such as 6C, 12C, 30C or 200C.
Liquid dilutions in alcohol and water are also sold, and you take them as drops. Low decimal strengths such as 1X, 2X or 3X, and the undiluted mother tincture, may still hold real acid. They are handled in a different way from the high dilutions.
Some combination products list Acidum muriaticum on the label along with several other remedies.
Acidum muriaticum came into homeopathy in the early 1800s. It came through Samuel Hahnemann's provings, tests in which volunteers took a substance and wrote down their symptoms.
Homeopaths in the 1800s reached for it in typhoid-type fevers, when a patient slid down the bed from sheer exhaustion. That picture is still how homeopathic books describe it today, along with mouth ulcers and dark, tender haemorrhoids.
Its standing sits inside homeopathy only. It has no separate history in herbal medicine, Ayurveda or Traditional Chinese Medicine.
See a doctor straight away if you have a fever above 39C, a fever lasting more than three days, confusion, or you feel too weak to stand or drink.
Get urgent care for bleeding from the back passage, black or tarry stools, vomiting blood, or severe stomach pain.
Book an appointment if a mouth ulcer lasts more than three weeks, if you keep getting them, or if piles keep coming back. Call a poisons centre or emergency services immediately if anyone swallows concentrated acid or mother tincture, or gets it on skin or in the eyes.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
The published evidence for Acidum muriaticum is weak or absent. That usually means no controlled trial has tested it, not that a trial found it ineffective — the two are different, and we grade only what has been published.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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