Lac caninum in Homeopathy: Uses, Picture and Limits

Key takeaways

• Lac caninum is the picture of alternation. Classic texts describe pains that move from one side to the other and back again, in the throat, the head, the breasts or the limbs.
• Touch and jarring are unbearable. The best-known strand is breasts that swell and become exquisitely sore before the period, so that every step downstairs hurts.
• The mental side is low self-regard. The old authors describe a forgetful, anxious person who feels despised or of little worth.
• It is made from dog's milk. It is one of a handful of milk remedies and a specialist product rather than a common kit remedy.
• Breast changes come first. A new lump, nipple discharge, skin dimpling, one-sided pain that does not follow the cycle, or a red, hot breast with fever is a medical question before it is a homeopathic one.

What is Lac caninum made from?

Homeopathic Lac caninum is prepared from the milk of a domestic dog, Canis familiaris. Lac is Latin for milk and caninum means "of a dog"; our guide to reading Latin remedy names explains why labels keep these old Latin forms. The milk is diluted and succussed step by step to the potency on the label. At the common potencies the arithmetic says nothing of the original milk remains; our potencies guide explains what that means and why it is also the reason science is sceptical.

Lac caninum belongs to a small family of milk remedies in homeopathy, alongside preparations from cow's, goat's and other mammals' milk, most of them introduced in the late nineteenth century or much more recently. It is the oldest and best documented of them. Homeopathic histories trace the use of dog's milk back to classical folk medicine, usually citing Pliny, and say that nineteenth-century homeopaths revived it before proving it formally. Our guide to what is in a homeopathic remedy covers how animal sources like this are prepared.

Unlike many remedies on this site, the source is not poisonous. The point to be clear about is a different one: Lac caninum is a specialist remedy, not a common shelf product, and most people who come across the name meet it in a practitioner's case notes rather than a kit.

What is the Lac caninum picture?

The Lac caninum picture is a state that cannot stay in one place. Imagine a woman a few days before her period. Her breasts are swollen, hot and so tender that she holds them with her hands as she walks down the stairs, because every jolt hurts. Yesterday the soreness was mostly on the left; today it is on the right; tomorrow it may move back. She feels forgetful, writes lists and loses them, and is quietly convinced that she is doing everything badly and that others think little of her.

Classic texts make alternation the keynote. Boericke (1927) describes erratic pains that alternate sides, and gives the throat as the classic example: a sore throat that begins on one side, moves to the other, and returns, with shining, glazed-looking membranes. The same alternation is described in headaches and in rheumatic pains of the limbs. Kent's Lectures (1905) spend as much time on the mind: absent-mindedness, nervousness, anxiety, vivid fears, and a sense of being looked down on, which Kent took very seriously as part of the picture.

The breast strand is the one modern readers meet most often. The materia medica records swelling and soreness before the period, intolerance of the slightest jar, and the person supporting the breasts to move. The tradition reads the touch-sensitivity and the side-to-side movement together; without both, the case is read differently.

What makes it better or worse?

The traditional modalities centre on touch, jarring and the cycle. Boericke (1927) gives Lac caninum as worse from touch and jar and better from cold and cold drinks.

The alternation is a modality in the sense homeopaths use the word: a feature of how the complaint behaves rather than what it is. Our guide to modalities, better and worse explains why that kind of detail outranks the name of a complaint.

What is Lac caninum traditionally discussed for?

In homeopathic literature, Lac caninum is traditionally discussed for pains that alternate sides and for touch-sensitive, cycle-linked breast soreness. On this site it appears on one acute page, where the Lac caninum-like pattern sits beside its neighbours and the red flags come first.

Breasts and the cycle

• Extreme sensitivity and wandering pains before the period: cyclical breast tenderness. That page sets the Lac caninum-like pattern beside the weepy Pulsatilla-like and the hard, heavy Conium-like pictures.

Throats that change sides

• The classic texts' most famous Lac caninum description, a sore throat that alternates sides. Our page on the first day of a sore throat covers other pictures and sets out the red flags for throats, including difficulty swallowing saliva or breathing.

Mood before the period

• The forgetful, anxious, self-doubting state the old authors describe. Our page on premenstrual irritability covers neighbouring pictures.

What is Lac caninum not?

Lac caninum is not "the breast-pain remedy". Cyclical breast tenderness is common, and the tradition describes several pictures for it, separated by what the soreness is like and what changes it. Lac caninum's description is the alternation from side to side, the extreme intolerance of a jar and the low self-regard. Breast soreness without those features is read as something else.

More importantly, breast symptoms carry their own red flags that no remedy picture changes. A new lump or thickening, a change in the shape or skin of a breast, dimpling or puckering, nipple discharge (especially bloody), a nipple that turns inwards, pain in one spot that does not follow the cycle, any new breast pain after the menopause, or a breast that is red, hot and painful with fever all need a clinician. A sore throat with difficulty swallowing saliva, drooling, a muffled voice or breathing difficulty is urgent. Our guide to red flags first sets out the principle.

Homeopaths separate it from its neighbours like this:

What potencies is Lac caninum sold in?

Lac caninum is sold mainly as 30C and 200C pellets by homeopathic manufacturers and specialist pharmacies; it is rarely found on a general pharmacy shelf or in home kits. Potency describes the preparation process, not an amount of milk: 30C means thirty successive 1:100 dilutions with succussion between them. Our potencies guide explains the scale and what remains in the vial.

This page deliberately gives no frequency or instructions for taking Lac caninum. That depends on a whole case, not a remedy name. Read the product label, and talk to a qualified practitioner about an individual situation.

What remedy lists don't tell you

Two things the "remedies for breast tenderness" lists leave out:

• How a symptom moves can matter more than where it is. Lac caninum is one of the clearest examples of a remedy defined by behaviour rather than location: a throat, a head or a breast, as long as the pain jumps sides. Lists sorted by body part lose that entirely, which is why our guide to the symptoms alongside the symptom asks what the complaint does, not only where it is.
• The mental picture deserves care. Kent and later authors gave great weight to Lac caninum's low self-regard. That is a description in an old text, not a label to apply to a person, and a persistent sense of worthlessness is a reason to talk to a doctor rather than a reason to match a remedy. The old authors were describing how a state hangs together, and the most useful reading keeps that distinction clear.