Propolis is a resinous substance that honeybees make by collecting plant resins, mainly from tree bark and leaf buds, and mixing them with wax and their own secretions. Sometimes called “bee glue,” it serves as the hive’s building material, disinfectant, and defensive barrier all in one. Raw propolis is roughly 50% resin, 30% wax, 10% essential oils, 5% pollen, and 5% other organic material. It has been used in traditional medicine for thousands of years and is now widely sold as a supplement in tinctures, sprays, capsules, and toothpastes.
How Bees Use Propolis in the Hive
Inside a hive, propolis plays both a structural and a sanitary role. Bees line the rough inner walls of their nest with it, creating a smooth, rigid surface. They seal cracks, block alternate entrances that could let in predators, and use it to reinforce weak points in the comb structure.
The sanitary function is equally important. Propolis contains compounds that kill bacteria and fungi, so coating the hive interior with it reduces the overall pathogen load. This passive disinfection means individual bees don’t have to mount as strong an immune response, saving energy for the colony. In one of the more striking examples of this behavior, when a large intruder like a mouse dies inside the hive and is too big to remove, bees will encase the entire carcass in propolis to prevent it from decomposing and spreading disease.
What Makes Propolis Biologically Active
Propolis contains over 1,000 identified compounds, but the ones that matter most for health effects are flavonoids and phenolic acids. These are the same types of protective plant chemicals found in fruits, vegetables, and tea, but in unusually high concentrations. Ethanolic extracts of propolis contain between 190 and 317 milligrams of phenolic compounds per gram, with flavonoid content ranging from about 53 to 79 milligrams per gram.
Flavonoids act as antioxidants by neutralizing free radicals, the unstable molecules that damage cells and contribute to aging and chronic disease. They essentially intercept these reactive molecules before they can harm cell membranes and DNA. Phenolic acids work alongside flavonoids by blocking the production of reactive oxygen species in the first place, adding a second layer of cellular protection.
The antibacterial effects work through several mechanisms at once. Propolis compounds interfere with bacterial DNA replication, disrupt the electrical charge across bacterial cell membranes, and reduce the energy production bacteria need to survive and multiply. Because so many different compounds contribute to this effect, researchers believe the antibacterial power comes from a synergistic interaction rather than any single molecule. This complexity also makes it harder for bacteria to develop resistance compared to a single-target antibiotic.
Types of Propolis
Not all propolis is the same. Its color, chemical profile, and potency depend on which plants the bees forage from, which in turn depends on geography. In temperate climates like Europe and North America, bees primarily collect resin from poplar trees, producing the classic brown propolis. In tropical regions where no poplars grow, bees adapt to local vegetation, creating chemically distinct varieties.
Green propolis, produced mainly in Brazil, comes from a single plant source in the daisy family. Its signature compounds are prenylated coumaric acids, particularly one called artepillin C. Red propolis, also Brazilian, originates from tropical legume and clusiaceae trees and is rich in isoflavonoids and chalcones, compounds more commonly associated with soy. Brown propolis from southern Brazil draws from pine, eucalyptus, and araucaria trees, giving it a profile heavy in caffeoylquinic acids and flavonols. Each type has been studied for slightly different health applications, but all share the core flavonoid and phenolic acid activity that gives propolis its biological effects.
Oral Health Benefits
One of the best-supported uses of propolis is in dental care. Greek and Roman physicians originally used it as a mouth disinfectant, and modern research has backed this up. A 2024 meta-analysis of clinical trials found that alcohol-free propolis mouthwash produced statistically significant reductions in both dental plaque and gum inflammation. Several of the individual studies compared propolis directly to chlorhexidine, the gold-standard prescription mouthwash, and found propolis performed equally well or better.
In one 21-day trial, propolis mouthwash outperformed chlorhexidine in reducing both gum inflammation and plaque scores. Another study found that propolis was the most effective option specifically for reducing gum inflammation, even when chlorhexidine was better at plaque removal alone. Propolis toothpaste has shown similar results, consistently producing lower plaque and inflammation scores compared to conventional toothpaste. The advantage of propolis-based oral products is that they don’t cause the tooth staining or taste disruption that chlorhexidine is known for.
How Propolis Supplements Are Made
Raw propolis is sticky and hard to use directly, so it is almost always processed into an extract. The extraction method matters because it determines which active compounds end up in the final product.
Ethanol (alcohol) extraction is the traditional and most common method. It is particularly good at pulling out flavonoids: ethanol extracts contain about 2.3 times more total flavonoids than water-based extracts. Specific flavonoids like galangin and certain glycosides were 14 to 16 times more concentrated in ethanol extracts. Water-based extracts, on the other hand, are better at extracting phenolic acids. Caffeic, sinapic, and chlorogenic acids were three to five times higher in water-based extracts. The total phenolic content ends up similar between the two methods (around 400 to 430 micrograms per milliliter), but the balance of compounds is quite different.
For people who want to avoid alcohol, water-based or glycerin-based tinctures are available. These deliver more of the phenolic acid benefits but less of the flavonoid content. Alcohol-based tinctures offer a broader spectrum of flavonoids, which are the compounds most closely linked to antioxidant activity. Capsules typically contain dried, powdered extract from one method or the other.
Safety and Allergic Reactions
Propolis is generally well tolerated, but it can trigger allergic reactions in certain people. Those with allergies to bee stings, other bee products like royal jelly, poplar tree products, or Balsam of Peru are at higher risk. Reactions can range from skin irritation and contact dermatitis to more significant allergic responses. The American Academy of Allergy, Asthma, and Immunology has noted that children who react to propolis sprays are likely allergic to one of its plant-derived components and should avoid further use.
There are no well-established dosage guidelines for propolis supplements. Clinical trials have used widely varying amounts, and no regulatory body has set a standard recommended dose. If you’re trying propolis for the first time, starting with a small amount to check for sensitivity is a practical approach, especially if you have any history of plant or pollen allergies.