What is Acidum hydrocyanicum?

Acidum hydrocyanicum is a single homeopathic remedy. Its Latin name is Acidum hydrocyanicum, and it is also sold as Prussic acid. Homeopaths have reached for it for sudden collapse states with gasping breath, blue lips, cold skin and near-fainting.

The starting material is hydrocyanic acid, better known as cyanide. It is one of the fastest-acting poisons known. The remedy is not that liquid: it is made by serial dilution, where one drop is diluted again and again, with hard shaking at each step.

At 30C, the strength most shops sell, essentially none of the source material is left. What you swallow is a sugar pellet or plain water in alcohol. That also means a 30C pill cannot poison you.

The honest verdict on effect is short. Trial evidence does not tell homeopathic remedies apart from placebo (a dummy treatment), and no trial has tested this remedy on its own. It has a place in homeopathic books going back to the 1800s, but traditional use is not proof that something works — that point applies to everything below and is not repeated.

One warning belongs here, at the front. The symptoms this remedy is traditionally linked to — collapse, gasping, seizures, chest pain — are emergencies. They need an ambulance, not a pill.

How does Acidum hydrocyanicum work?

There is no accepted way for this remedy to act in the body, because at 30C there is nothing of the source substance in it.

Homeopathy works from two ideas. The first is "like cures like": a substance that causes certain signs in a healthy person is used, in tiny form, for a sick person with similar signs. Cyanide causes gasping, blue lips and collapse, so it was matched to those pictures.

The second idea is that shaking at each dilution step leaves an imprint or "energy" in the water. Chemistry and physics do not support this. Past about 12C, no molecules of the original material remain.

So any benefit people report is best explained by the natural course of the illness, by other care being given at the same time, and by placebo effect (feeling better because you expect to).

What forms does Acidum hydrocyanicum come in?

The usual retail forms are sugar pellets and liquid drops, most often at 30C or 200C.

Pellets are small sugar globules soaked with the diluted liquid. They are meant to be melted under the tongue.

Liquid drops are kept in alcohol and water. They come in a dropper bottle and are usually taken in a little water.

You may also see 6C and 12C tubes, and combination products where this remedy is one name on a long list. Mother tincture and low X strengths, such as 1X to 6X, should not be bought at all for this substance.

Check the label for the potency before you buy. If the strength is missing or unclear, put the product back.

Where it comes from:

Hydrocyanic acid was isolated in the late 1700s and quickly became known as a fast poison. Homeopaths tested it on healthy volunteers in the 1800s and wrote up the symptoms it produced.

It entered homeopathic materia medica through 19th-century writers such as Hering and Allen. It was used for cholera-type collapse, convulsions, spasmodic breathing and heart symptoms in an era with few other options.

It has never been a mainstream, everyday homeopathic remedy. It sits in the smaller group of acid remedies used for dramatic, sudden pictures, which is why its traditional standing is recognised rather than central.

What does Acidum hydrocyanicum help with?

• Sudden faintness and collapse states: Homeopathic books give one classic picture here. It is cold skin, blue lips, a weak pulse and near-fainting. No human trial has tested the remedy for it. Collapse has serious causes, such as heart trouble or blood loss. Treat it as an emergency and call for help.
• Gasping or spasmodic breathing: Old homeopathic texts match it to breathing that comes in gasps, with a feeling of choking. There is no trial evidence here at all. Trouble breathing needs urgent medical care. Never swap asthma or heart failure medicine for pellets.
• Convulsions and seizure-like states: Cyanide poisoning can cause fits, so homeopaths matched the remedy to fit-like states. No human study supports this use. Epilepsy (a condition that causes repeated fits) needs prescribed medicine. Stopping that medicine can be dangerous.
• Palpitations and chest tightness: Older sources link it to a pounding or uneven heartbeat with fear and cold sweat. There is no trial evidence for this. Chest pain or a racing heart with sweating or breathlessness can mean a heart attack. Get checked the same day.
• Violent vomiting and cramping, cholera-type pictures: This use goes back to cholera outbreaks in the 1800s, and it is of historical interest only. Today, bad vomiting and diarrhoea are treated with fluids and by treating the cause. Dehydration (too little water in the body) can turn serious fast in babies, older adults and anyone frail.

Which foods are rich in Acidum hydrocyanicum?

1. Bitter almonds: contain a compound that releases cyanide when chewed
2. Apricot and peach kernels: the same compound, sold wrongly as a health food
3. Apple and cherry pips: tiny amounts, harmless if swallowed whole and not crushed
4. Cassava root, if not soaked and cooked properly: a known cause of poisoning

Practical Tips:

These foods are not a form of the remedy, and eating apricot kernels for health has caused real poisonings and deaths.

What are the side effects of Acidum hydrocyanicum?

• No direct effects expected from 30C or higher, as no source material remains
• Sugar load from pellets, which matters if you count sugar or avoid lactose (milk sugar)
• Alcohol content in liquid drops, a problem for some adults and for children
• A short flare of symptoms, called an aggravation by homeopaths, which is not proven to be real
• Delay in getting real treatment: the main and most serious risk
• Genuine cyanide poisoning if a low-potency or mother tincture product is swallowed

Good to know:

A 30C pellet is chemically inert, so direct side effects are rare and mild when they happen.

The serious risks lie elsewhere. One is delay: using this instead of emergency care for collapse, seizures, chest pain or breathing trouble can cost a life. The other is buying a strength low enough to still contain cyanide.

Signs of cyanide harm include a sudden headache, dizziness, confusion, a fast then slow pulse, gasping and collapse. That is an emergency: call an ambulance straight away.

How much Acidum hydrocyanicum should you take?

• Recommended daily: No dose has been established by research, because no trial has shown a dose that works better than placebo. What labels usually say is 3 to 5 pellets of 30C, or a few drops in water, taken two or three times a day. Homeopaths often use less than that and stop as soon as things improve. Two firm limits apply. Never use the mother tincture or any strength below 12C, and never use any dose as a stand-in for emergency care.
• Best time of day: There is no evidence for any particular time. Homeopathic practice is to take it when symptoms are present, spaced through the day, rather than on a fixed schedule.
• With or without food: Usually taken away from food. The common practice is to keep the mouth clear of food, drink, toothpaste and strong flavours for about 15 minutes either side, and to let pellets melt under the tongue. This is custom, not tested science.
• Time to effect: No reliable time to effect can be given, because no trial has shown an effect beyond placebo. Homeopaths expect a response within minutes to hours in acute pictures. If you are waiting on a pill during a breathing, heart or seizure problem, you are waiting too long — call for help.
• How long to take it: Keep it short. A few days is the most anyone should use it without advice. The complaints it is traditionally linked to are sudden and serious, so waiting to see what happens is the wrong plan. If your symptoms are not clearly better within 48 hours, or get worse at any point, stop and get medical care.