Ichthammol ointment is the most widely used and effective over-the-counter drawing salve for boils. It comes in two standard concentrations, 10% and 20%, with the 20% version being the stronger option for deeper or more stubborn boils. While no drawing salve has been through the kind of rigorous clinical trials you’d see for a prescription drug, ichthammol has been used for well over a century and remains the go-to recommendation at most pharmacies.
How Drawing Salves Actually Work
The term “drawing salve” refers to an ointment that helps bring pus and fluid closer to the skin’s surface, making it easier for a boil to drain on its own. Ichthammol, sometimes called ammonium bituminosulfonate, achieves this through a specific mechanism: it loosens the outer layers of skin and increases skin permeability in a concentration-dependent way. A 2022 lab study using 3D skin models confirmed that the substance interacts with structural proteins in the outer skin layer, softening the tissue above the trapped infection. This loosening effect is what allows pus to move upward and eventually break through.
It’s worth noting that a drawing salve doesn’t kill bacteria the way an antibiotic would. Its job is mechanical, not antimicrobial. It creates conditions for the boil to come to a head and drain naturally.
Ichthammol: 10% vs. 20%
Most drugstores carry ichthammol in either 10% or 20% strength. The 20% formulation is more effective for boils because the skin-loosening effect scales with concentration. If you’re dealing with a small, shallow boil that’s already close to the surface, 10% may be sufficient. For deeper, more painful boils that haven’t yet formed a visible head, the 20% version is the better choice.
Ichthammol ointment is dark brown or black with a distinctive tar-like smell, and it can stain fabric yellow. Keep that in mind when choosing bandages and clothing. The base is typically petrolatum (petroleum jelly), which keeps the active ingredient in contact with the skin and helps soften the area further.
How to Apply a Drawing Salve
Proper application makes a significant difference in how well the salve works:
- Clean the area first. Wash the skin around the boil gently with warm water and soap.
- Apply a generous layer. Spread the ointment directly over the boil, covering it completely.
- Cover with a gauze bandage. This keeps the salve in place and protects your clothing from stains.
- Reapply once or twice daily. Remove the old bandage, clean the area again, and apply a fresh layer with a new bandage.
- Do not squeeze, rub, or massage the boil. Pressing on a boil can push the infection deeper into surrounding tissue.
Most boils that respond to a drawing salve will come to a head within a few days of consistent application. Some take up to a week. Once the boil drains, keep the area clean and loosely covered until it heals.
Natural and Herbal Drawing Salves
If you prefer a plant-based option, herbal drawing salves typically combine an oil infused with plantain leaf, comfrey, and calendula, thickened with beeswax and sometimes boosted with activated charcoal. Activated charcoal is included for its absorptive properties, while plantain has a long folk-medicine history as a poultice herb for pulling irritants from the skin.
These herbal salves can work for minor skin irritations and splinters, but they lack the proven skin-loosening mechanism that makes ichthammol effective on deeper boils. If you’re dealing with a painful, well-established boil, ichthammol is the more reliable choice. Herbal salves are better suited as a gentle first step for smaller bumps or for people who find ichthammol’s smell or texture unpleasant.
Drawing Salve vs. Black Salve
One critical distinction: drawing salve and “black salve” are not the same thing. Black salve typically contains bloodroot or zinc chloride and is marketed as an alternative remedy for skin growths and even skin cancer. It is corrosive and can cause severe tissue destruction. The FDA has warned against its use, and the American Academy of Dermatology has stated there is no credible evidence supporting its claims. There is no antidote or reversal agent for black salve damage. If a product contains bloodroot (Sanguinaria canadensis), avoid it entirely.
Standard ichthammol drawing salve, by contrast, is not corrosive. It works by softening skin, not by burning through it.
Side Effects to Watch For
Ichthammol ointment is generally well tolerated. The most common side effects are mild skin irritation, redness, dryness, or temporary skin discoloration at the application site. These typically resolve once you stop using the product.
Allergic reactions are rare but possible. Signs include a skin rash, itching, hives, or swelling around the face, lips, or throat. You should also avoid applying ichthammol to large areas of burned or broken skin, as increased absorption through damaged skin could cause irritation.
Signs a Boil Needs More Than a Salve
Drawing salves work well for uncomplicated boils, but some infections progress beyond what a topical ointment can handle. A boil that doesn’t improve after a week of consistent salve use, or one that continues growing, likely needs professional drainage. Red streaks spreading outward from the boil suggest the infection is moving into surrounding tissue, a condition called cellulitis that can spread rapidly and requires antibiotics. A fever alongside a boil is another clear signal that the infection has moved beyond the skin’s surface. Any boil larger than about two inches across, or one that develops in a high-risk area like the face or spine, warrants professional evaluation rather than home treatment alone.