Educational information, not medical advice — ask your doctor or midwife.
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Causticum is a single homeopathic remedy. Its Latin name is Causticum Hahnemanni. It is also known as Hahnemann's tinctura acris sine kali, a potassium hydrate compound.
Homeopaths give it to people who feel weak, stiff and worn down. Common reasons are leaking urine, warts, a hoarse voice and aching joints. It has been used this way for about 200 years.
The remedy is diluted again and again. At 30C no source material is left in the pill. Trials do not show it beats a dummy pill (placebo), and long use in a tradition is not proof of effect.
There is no known way for Causticum to act on the body. At 30C, nothing of the source is left. So there is nothing there to have a drug-like effect.
Homeopathy rests on two ideas. The first is "like cures like": a substance that causes signs in a well person is said to treat the same signs in a sick person. The second is that shaking the liquid at each step (called succussion) leaves behind an imprint.
Chemistry and physics do not support the second idea. Trial results mostly match placebo. Any change you feel is more likely to come from time, from care and attention, or from the visit itself.
Causticum comes as small sugar pillules. You let them melt under the tongue. Tablets, granules and liquid drops are also sold.
Strengths are written as 6C, 30C or 200C. The C means a 1-in-100 dilution step, repeated that many times. A higher number means more steps, not more substance.
30C is the most common strength in shops. Some countries also sell creams that name Causticum on the label. Check the label if you avoid lactose (milk sugar).
Samuel Hahnemann made Causticum himself in the 1820s. He was the German doctor who founded homeopathy. He wrote it up in his book on long-term illness in 1828.
He made it by distilling slaked lime with potassium bisulphate. He named it tinctura acris sine kali, which means "sharp tincture without potash".
It became one of homeopathy's polychrests, meaning remedies used for many different complaints. It is still taught and stocked today. It has no place in other healing traditions.
See a doctor if your voice stays hoarse for more than three weeks, or if a wart bleeds, changes colour or grows fast. Book a visit if leaking urine is new, painful, or comes with blood or a burning feeling. Also get checked if joint pain, weakness or numbness is getting worse. Call emergency services for a sudden face droop, a weak arm, slurred speech, chest pain or trouble breathing.
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 Causticum 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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