What is Causticum?

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.

How does Causticum work?

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.

What forms does Causticum come in?

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).

Where it comes from:

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.

What does Causticum help with?

• Leaking urine when you cough, laugh or sneeze: This is the best known homeopathic use for Causticum. Homeopaths pick it when the leak comes with a cough, a laugh or a sneeze, and is worse in cold weather. No human trial has tested Causticum for this. Pelvic floor exercises do have trial support, so ask your doctor or a physiotherapist about them.
• Warts: Homeopaths choose it for warts near the nails or on the face, and for warts that bleed. There is no trial evidence that it clears warts. Most warts fade on their own in months to a couple of years. A pharmacist can advise on treatments that are tested.
• Hoarse voice and loss of voice: Tradition links it to a raw, hoarse voice that is worse in the morning. There is no trial evidence for this use. A hoarse voice that lasts more than three weeks needs a doctor's check.
• Weak face muscles after Bell's palsy (sudden face droop): Homeopaths have long used it for face weakness that lingers after the sudden droop. No trials support this. A new face droop is an emergency, because it can also be a sign of a stroke. Call emergency services straight away.
• Stiff, aching joints and tight tendons: The old picture is stiffness that eases in damp, warm weather and worsens in dry cold. There is no trial evidence that it helps joint pain. Ongoing joint pain should be looked at by a doctor, since treatment depends on the cause.
• Old burns and scars that still hurt: Homeopaths sometimes give it for burns that healed badly or scars that still ache. No human trials have tested this. Fresh burns need cool running water and, if deep or large, urgent medical care.
• Restless legs at night: Tradition links it to twitching, jerking legs that keep you awake. There is no trial evidence here either. Restless legs can be tied to low iron, so a blood test is worth asking about.

What are the side effects of Causticum?

• No direct side effects are expected, since nothing of the source remains at 30C
• Wind, bloating or loose stools in people who react to lactose (milk sugar)
• Rare rash or itch, usually from the sugar or the alcohol in drops
• A short flare of symptoms, which homeopaths call an aggravation and which has not been shown in trials
• Delay of care that works, which is the main real risk

Good to know:

Harm from the remedy itself is very unlikely. The pills are sugar, and the liquid is alcohol and water. The bigger worry is what you might not do while taking it, such as putting off a check-up or stopping a drug you need.

How much Causticum should you take?

• Recommended daily: No dose is proven, because no trial shows the remedy works. In practice, homeopaths most often use 30C. A common pattern is 3 to 5 pillules under the tongue, once to three times a day. Higher strengths such as 200C are usually given less often. Follow the pack or the person who prescribed it. Taking extra pillules does not raise the strength. It only raises the amount of sugar you eat.
• Best time of day: Any time of day. Many homeopaths suggest the morning and bedtime. There is no evidence that timing changes anything.
• With or without food: Homeopaths advise taking it about 15 minutes away from food, drink, toothpaste and strong tastes. There is no evidence this matters. It is harmless either way.
• Time to effect: No reliable time can be given, because the remedy has not been shown to work. Any change you notice cannot be told apart from normal ups and downs.
• How long to take it: Keep any trial short. Homeopaths often review a sudden problem within a few days, and a long-standing one after 4 to 6 weeks. If nothing has changed, stop and look at other options.