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Evidence Based

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What Is the Strongest Candida Killer?

Written by Dr. Michael Ruscio, DC on July 3, 2025

Written by Dr. Michael Ruscio, DC on July 3, 2025 — Reviewed by Hannah Wright

• What Is Candida?|
• Antifungal Drugs|
• Probiotics|
• Herbal Antimicrobials|
• Diet|
• Lifestyle|
• Candida Myths|

If you have a Candida overgrowth, you’ll want to get rid of this fungal infection as quickly as possible so you can start feeling better. 

The strongest Candida killers are generally recognized to be antifungal drugs, such as fluconazole (brand name Diflucan), nystatin, and clotrimazole. 

However, this doesn’t necessarily mean drugs are the best long-term approach for fighting Candida. Many people do better with herbal antimicrobials, taken either in addition to or as an alternative to standard antifungal drugs. 

Probiotics can also play an important role in keeping the microbiome healthy and preventing the inappropriate growth of Candida species.

In this article, we’ll take a comprehensive look at Candida infections and at the treatments that can help to cure and prevent them.

What Is Candida?

Candida is a yeast that normally lives harmlessly in the body’s microbiomes 1, but when it overgrows, it can lead to infections of the mouth (oral thrush), gut, genitals (yeast infections), or skin. Candida albicans is the most common species, but Candida infections are associated with symptoms like:

• Genital itching, burning, redness, and thick white or yellow discharge 2 3
• Creamy white patches or spots on the inside of the mouth 4
• Digestive problems (pain, gas, bloating, nausea, diarrhea) 5
• Worsened irritable bowel syndrome 6
• More inflammatory bowel disease flare-ups 7
• Anxiety 8
• Depression 9
• Chronic fatigue 10
• Brain fog 11 12
• Discolored, brittle nails 13

In the clinic, our clients with Candida overgrowth also often have food intolerances and carb cravings.

Though the body usually keeps it in check 14, Candida is an opportunistic organism—it can become problematic when the body’s internal balance is disrupted. It also forms biofilms, which are dense microbial communities that grow on mucosal surfaces and medical devices, making infections harder to treat 15.

An overgrowth may be triggered by many factors, such as:

• Steroid use 16
• Chemotherapy 16
• Diabetes 16
• Pregnancy 16
• Oral contraceptive use 16
• A compromised immune system 16
• Tight, non-breathable clothing 16
• Acid-lowering medications 5 
• Chronic stress 17
• Antibiotics 18
• Lack of physical activity 19
• Alcohol 20
• Diets high in fat, sugar, and processed foods 17
• Smoking 16

These factors can weaken the body’s microbial defenses and create an environment where Candida can thrive.

Pharmaceuticals Are the Strongest Candida Killers

Prescription antifungals are the strongest Candida killers and usually clear infections quickly and effectively 21. Two commonly prescribed antifungals are fluconazole/Diflucan (for all types of Candida) and nystatin (for oral thrush). 

Fluconazole is considered more reliable because it’s absorbed into the bloodstream and works throughout the body 22. In contrast, nystatin isn’t absorbed and only exerts its antifungal properties locally, on the mucosal surfaces it directly contacts 23.

Downsides of Antifungal Drugs

Antifungal drugs used to treat Candida infections usually cause only mild side effects, such as mouth irritation or digestive issues like nausea, vomiting, diarrhea, or stomach upset 22 24. However, infections often return once treatment stops. 

In one study, only 8% of women with recurrent vaginal thrush had flare-ups during six months of fluconazole (Diflucan) treatment, compared with 64% of those on a placebo. But six months after stopping treatment, recurrence rates in the fluconazole group rose to 57% 25. 

This suggests to me that a deeper imbalance—typically of the gut microbiome—exists in the body, and the antifungal drugs don’t address it.

Another problem with treating recurring Candida infections with antifungal drugs is that repeated use increases the risk of drug resistance 26.

To treat an infection and reduce recurrence and the risk of drug resistance, I address the underlying microbial imbalance that’s allowing Candida to get out of hand. In the clinic, we typically start with probiotics and herbal antimicrobials alongside a diet that supports a healthy gut microbiome. 

Given how effective this is, we reserve antifungal drugs for rare cases that need an extra push.

Probiotics for Candida

Probiotics are supplements containing beneficial gut bacteria that can help crowd out harmful microbes and support a healthier microbial balance—of bacteria and fungi—throughout the digestive tract. 

Though they aren’t the strongest Candida killers, multiple studies suggest probiotics may play a solid supportive role in managing Candida infections, even outside the gut. For example:

• A meta-analysis (study of studies) found that probiotics combined with antifungals like fluconazole were more effective for treating vaginal Candida than antifungals or placebo alone. Probiotics alone didn’t consistently improve symptoms or test results, but they may have helped prevent further infections 27.
• Three meta-analyses have shown that probiotics can reduce oral Candida, especially in people with dentures 28 29 30.

At the clinic, we have extensive experience using probiotics as part of a successful treatment regimen for clients with Candida infections.

The Role of Herbal Antimicrobials

A number of herbal treatments for Candida overgrowth may also be clinically effective against overgrown Candida. The following herbs with strong antimicrobial properties have shown specific anti-Candida or anti-biofilm activity. 

• Oregano Oil: Oregano oil is one of the most potent antifungal herbs in lab studies, outperforming other oils against Candida in petri dishes 31. Though human trials are lacking, we’ve found oregano oil is highly effective against intestinal Candida in the clinic, particularly as an ingredient in Biota-Clear 1a and Biota-Clear 2b.
  
• Garlic Tablets: Garlic contains allicin, which has strong antifungal effects—a randomized controlled trial (gold-standard type of experiment) found garlic extract as effective as fluconazole for vaginal Candida 32. We use Garlic Select for both gut and vaginal Candida infections, typically at 1,500 mg/day.
  
• Cinnamon & Lemongrass Oils: Lab research shows that cinnamon and lemongrass oils can reduce Candida albicans in a petri dish by more than 99% 33. Although clinical evidence is limited, these oils—along with garlic—have worked well for treating oral Candida in our clinic.
  
• Horopito (Kolorex): Horopito (Pseudowintera colorata) has antifungal and anti-biofilm effects—two clinical trials found it more effective than the drug itraconazole for vaginal Candida infections 34 35. We often start with 2.5 mg/day of a Horopito product called Kolorex, increasing to 5 mg if tolerated.

In the clinic, combining antimicrobial herbs with probiotics has been highly effective for combating overgrown Candida.

Herbs Have a Safer Profile

Although more research is needed to pinpoint which herbs or combinations work best for overgrown Candida, current evidence—including a systematic review 36—and our clinical experience suggest that people generally tolerate herbal antifungals better than pharmaceuticals. 

Herbs like oregano and garlic oil also pose less risk of promoting antifungal resistance. Unlike pharmaceutical drugs, which typically target a single pathway, herbal compounds act through multiple mechanisms, making it harder for fungi to adapt and develop resistance to them 37.

Diet and Candida

Diet plays an important role in supporting gut health and may help manage a Candida overgrowth, especially when used alongside probiotics and antimicrobial herbs. 

A clinical trial involving 120 people with gut Candida and digestive symptoms found that what they ate may have significantly improved treatment results. All participants were given the antifungal drug nystatin for 10 days, but only half of them also followed a Candida-focused diet for 3 months. In the medication-only group, 42.5% were symptom-free and had cleared the yeast. In contrast, a whopping 85% of those who combined nystatin with dietary changes were symptom-free and Candida-free 38. 

This wasn’t a randomized placebo-controlled study, so we can’t be sure what caused what, but this research and our clinical experience suggest that a whole-foods, low-sugar diet can play a significant role in helping to clear an infection. This makes sense because a healthy gut microbiome can have a big impact on Candida numbers, and what you eat is perhaps the best way to support your gut.

In the clinic, the most effective dietary strategy includes an anti-inflammatory diet with fewer sugars that may feed yeast. The diet we recommend is designed to support gut health and provide foods with natural antifungal properties. For a detailed guide on what we coach our clients to eat when they have a Candida overgrowth, check out our Candida Diet Handout.

Lifestyle and Candida

Reducing stress 39 and exercising 40 are important elements of treating and preventing a Candida overgrowth. Ignoring stress management, your need for rest, and daily movement is like taking the scaffolding out from under the immune system. It will have to work much harder and it’ll be less effective at keeping Candida numbers in check. 

It’s also important to brush your teeth at least twice a day to help limit the numbers of oral Candida that get into the GI tract 1.

Squashing Candida Myths

Several common myths about Candida infections persist in popular health discussions, despite lacking scientific support.

Myth 1: Candida infections only affect women.

• Reality: Though vaginal yeast infections are common, Candida can infect anyone, regardless of gender. Oral thrush, skin infections, yeast infections, and even systemic (invasive) candidiasis can occur in men, women, and children.

Myth 2: All chronic health problems are caused by Candida overgrowth.

• Reality: Fatigue, joint pain, brain fog, and weight gain are often blamed on Candida, but these full-body symptoms usually stem from deeper imbalances in the body. Candida infections are typically localized and don’t cause widespread symptoms in healthy people. That said, an overgrowth can occur alongside chronic gut issues, which may cause whole-body symptoms.

Myth 3: Strict “anti-Candida diets” are necessary to cure infections.

• Reality: There is no strong clinical evidence that eliminating sugar, yeast, or certain foods alone can cure or significantly impact Candida infections. Our clinic uses probiotics and herbal antimicrobials (or antifungal medications if needed) along with a healthy diet and lifestyle to support gut health and immune function.

Myth 4: Candida infections are always a sign of poor hygiene.

• Reality: Candida is a normal part of the human microbiome. Infections often result from changes in immunity, antibiotic use, or underlying health conditions—not simply hygiene practices.

Focusing solely on combating Candida can lead you away from treating the root cause of the overgrowth. A more effective approach is to improve overall gut health through targeted diet and lifestyle changes.

Overcoming Candida Infections

Prescription antifungals like fluconazole and nystatin are the strongest Candida killers, but they don’t address the root cause—typically an imbalance in gut microbes. Infections often return after treatment, and long-term use increases the risk of drug resistance. For these reasons, we usually reserve antifungal drugs for more severe or stubborn cases.

A more sustainable approach combines probiotics, antifungal herbs, and a gut-friendly, low-sugar diet. This helps rebalance the microbiome and lowers the risk of recurrence. Lifestyle habits like stress reduction, regular movement, and good oral hygiene also play an important role in keeping Candida in check.

If you’ve struggled with Candida infections and want more information on how to treat them, consider scheduling a virtual or in-person consultation at the Ruscio Institute for Functional Health clinic, or learn about my 8-step protocol for restoring your digestive system in Healthy Gut, Healthy You.

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