Grapefruit seed extract is made from the pulp, seeds, and membranes of grapefruits. It’s long been used as an alternative, unproven remedy for a number of health conditions, including candida infections.

The extract is most often found as a liquid concentrate, though there are some capsule or tablet forms, too.

While research showing effectiveness is limited, there’s some inconclusive scientific and anecdotal evidence that suggests this extract may help treat different types of candida infections. This may be due to its antifungal and antimicrobial properties. A 2015 review listed grapefruit seed extract as one of the plants with anticandida activity.

It’s possible that grapefruit seed extract may be more effective at treating certain kinds of candida infections than others.

Thrush is a candida infection that occurs in and around the mouth. Grapefruit seed extract’s antifungal and antimicrobial properties may be able to stop the growth of the yeast, and actually reduce the infection. No research exists currently that shows whether or not grapefruit seed extract is effective at treating thrush specifically.

To treat thrush with grapefruit seed extract, apply it to a Q-tip or cotton ball. If you have sensitive skin, you can first mix the extract with coconut oil, which has its own antifungal properties. Then, apply it directly to the affected area. Leave it to dry. You can do this twice daily. Make sure that your extract has citricidal as an active ingredient.

Currently, no studies show the potential effectiveness of grapefruit seed extract for vaginal yeast infections.

As an alternative treatment, the first line of defense would likely be to take the extract orally. You can take 3 capsules (or 10 to 20 drop of liquid) per day.

Don’t confuse grapefruit essential oils with grapefruit seed extract. Essential oils are not meant to be taken orally.

Athlete’s foot is a topical candida infection affecting moist areas on the feet. Because of this, topical administration of grapefruit seed extract might be effective.

Apply full-strength grapefruit seed extract to the affected area up to three times a day. Make sure to keep the area dry and clean. Change your socks regularly. You may want to add a vinegar foot soak as another natural treatment.

There’s some evidence that grapefruit seed extract may help with candidiasis of the skin. One older study on atopic eczema — which is associated with candida — found that ParaMycrodicine (which contains grapefruit seed extract) was effective against multiple strains of yeast. This included candidiasis. However, there has been no further research, and this study dates back to 1990.

Taking oral supplements can help treat widespread candidiasis of the skin, though applying grapefruit seed extract topically may also work well. Take up to three capsules, or 10 to 20 drops of liquid concentrate, daily. You can also apply the extract directly to the affected area, using coconut oil if you have sensitive skin.

Candida yeast is a fungus, not a bacterium. Grapefruit seed extract’s best defense against candidiasis is its antifungal properties.

That being said, the extract does have strong antimicrobial and possible antibacterial properties as well. These may help with other conditions, like topical bacterial skin infections.

One study found that grapefruit seed extract may have comparable effectiveness in treating multiple types of bacteria strains as commonly prescribed topical antibiotics. This was a preliminary study so more research is needed.

Another study found that 5 out of 6 grapefruit seed extracts successfully inhibited growth against multiple bacterial strains. This study also found, however, that these benefits may have come from preservative agents found in the different extracts used.

Grapefruit seed has been studied as a way to reduce urinary tract infections for catheters, showing its strong antibacterial role.

If you believe you have a bacterial infection, talk to your doctor immediately. While they may approve alternative treatments like grapefruit seed extract, be aware that bacteria can spread quickly throughout the body.

If your doctor prescribes you antibiotics, take the full regimen exactly as prescribed.

In general, grapefruit seed extract is considered safe for most people to use, both on a short- and long-term basis. Although grapefruit juice is known to interact with many medications, this is generally not believed to be the case with the extract. However, you should still discuss its use with your doctor.

Though there’s anecdotal evidence that grapefruit seed extract can be helpful in treating candidiasis, it’s not without risk.

Grapefruit seed extracts are relatively unregulated by the Food and Drug Administration, just like most other extracts and ingredients that are used in alternative remedies. This means that they may not be pure, or that they may contain harmful additives that aren’t disclosed as a result of heavy processing.

One study even found that many grapefruit seed extracts that were commercially available contained dangerous ingredients like triclosan and benzethonium chloride.

This study reinforces an earlier study that found similar amounts of the same synthetic ingredients. Both studies indicate that the synthetic additives may be providing the antimicrobial action, not the natural grapefruit seed extract.

If you’re unsure about what treatment options to pursue, talk to your doctor. They may recommend coconut oil or diluted tea tree oil as alternative remedies instead. They may also opt for over-the-counter or prescription medications.

Your doctor can help you choose the safest and most effective treatment plan for you.