• Oral thrush is a fungal infection of the oral mucosa caused by Candida species. It is the most common human fungal infection.

  • Oral thrush may refer to candidiasis in the mouths of babies, or if occurring in the mouth or throat of adults it may also be termed candidosis or moniliasis, or pseudomembranous candidasis

  • Topical candidiasis is not normally a dangerous condition except in the rare cases when it enters the blood of people with weakened immune systems.

  • Candida is a normal component of oral flora in 50% of the population. Decrease in competitive bacteria population caused by broad spectrum antibiotic use may increase growth of Candida.

  • Candida may also occur in people who are treated with inhaled corticosteroids for asthma or rhinitis; in people who wear dentures; and in people with any form of immunosuppression (disease e.g., diabetes, AIDS or drugs e.g. chemotherapy, anti-rejection drugs taken by organ transplant patients).

  • Thrush occurs in up to 2 - 5% of normal newborns as it is acquired from their mothers at birth and may appear as early as 7 to 10 days of age. Use of antibiotics especially in the first year of life may lead to recurrent infection.  It is uncommon in children older than 1 year of age unless related to antibiotic use, immunosuppression or steroid inhaler use without post-use mouth rinsing.

  • Risk factors:
    • Medical conditions:
      • Immunosuppression
      • Malignancy
      • Sjogren's disease
      • Diabetes
      • Cushings disease
    • Medications:
      • Inhaled corticosteroids (if not rinsing mouth properly)
      • Recent broad-spectrum antibiotic use
      • Chemotherapy or radiation therapy
    • Age (newborns, or over 65)
    • Pregnancy
    • Dentures
    • Poor oral hygiene
    • Chronic dry mouth
  • For photos and more information go to :
    DermNet NZ

Three types of oral thrush to consider:
  1. Acute pseudomembranous candidiasis
    • Superficial, gray to white curd-like areas on lips, buccal mucosa, tongue and/or palate, which can be scraped off to reveal an erythematous base and cause mild bleeding.
    • Most often asymptomatic, but can cause mild pain
    • Fussiness and decreased feeding in infants
    • Concurrent candidal diaper dermatitis possible
    • May cause a cottony feeling in the mouth and loss of taste.

  2. Atrophic candidiasis
    • Chronic red edematous lesions
    • Common in elderly and under dentures

  3. Angular cheilitis
    • Corners of mouth cracked, red and moist

Oral thrush is diagnosed based on signs, symptoms and history. Rule out the following conditions that may present with similar signs / symptoms:

  • Periodontal infection - red swollen gums, bleeding gums, no white spots.  A key differentiating factor is that a periodontal infection will have significant swelling, but oral thrush will not. Refer to dentist or patient's primary care provider for counselling and / or prescription mouthwash (e.g. chlorhexidine 0.12 % oral rinse)

  • Burns will cause significant redness and swelling in the mouth, which should not be seen with oral thrush.  Common in bottle-fed infants.

  • Leukoplakia causes chronic lesions seen mostly in smokers and males over 30.  These are small, translucent white plaques, usually on the tongue.  The plaques cannot be wiped off as easily as oral thrush.  These lesions can be cancerous, so a biopsy is recommended if this condition is suspected.

  • Aphthous ulcers are one or more shallow, usually painful sores with a white coating.  They appear as discrete lesions, which helps differentiate it from oral thrush.
  • Herpes simplex infection is indicated by multiple ulcerous or vesicular lesions. Primary herpes (first episode) may also be associated with fever, swollen glands, poor appetite.

  • Coxsackievirus (hand, foot and mouth disease) usually occurs in children, manifests as small (1 - 2 mm), tender lesions usually on the posterior pharynx including tonsils, soft palate, uvula and raised areas on hands and feet. No need to refer, but recommend fluids to prevent dehydration.

  • Lichen planus  appears as inflammatory, scaly, white or striated patches possibly caused by local trauma to tissue.

  • Adverse drug reaction - sore mouth with diffuse redness and / or bullae / blisters on oral mucosa occuring after initiation of a new medication. Stevens Johnson Syndrome / Toxic Epidermal Necrolysis (rare) can occur from a few days up to 2 months after starting a medication.

Patients with signs / symptoms typical of oral thrush often do not require further investigation, however an assessment by the patient's primary care provider should be recommended in the following situations:

  • Patient is on chemotherapy or immunocompromised due to drug therapy or medical conditions.

  • Other organ involvement such as conjunctivitis, uveitis or accompanying genital ulcers.

  • Any lesion present for 3 weeks or longer should be referred to patient's primary care provider as it may require biopsy and/or systemic antifungal treatment.

  • Possible adverse drug reaction.  If a prescription medication is suspected, refer to patient's primary care provider for evaluation and possible change in medication.

  • Suspect viral herpes infection - multiple ulcerous or vesicular lesions. Refer to patient's primary care provider for evaluation.

  • Recent burn to the mouth.

  • Patient wears dentures AND has significant swelling as a symptom.
  • Unable to confirm diagnosis of oral thrush. Refer for further evaluation and / or supervised therapy

1. Non-pharmacological treatment:

  • Although thrush can be transmitted during breastfeeding, the incidence of this condition appears to be greater in infants who are formula-fed.  For this reason, sterilization of nipples and proper storage of formula is important. Nipples should be soaked in a solution of equal parts water and vinegar and allowed to air dry.

  • Mothers of breastfed infants should use nursing pads to stop transfer of organism to clothing. These should be washed frequently with bleach or disposable nursing pads should be used.

  • Optimal denture care must be done:

    • Remove dentures overnight

    • Wear for maximum of 6 hours per day during infection

    • Clean daily and soak in disinfectant overnight (e.g. with chlorhexidine)

    • Clean gums, tongue and affected areas with soft toothbrush

    • Ensure proper fit

  • Toothbrushes should be replaced often until infection clears up.

  • Rinse mouth after using steroid inhalers or nasal sprays. Use of aerochambers with oral inhalers can also help to prevent infection.

  • To soothe irritated mouth, dissolve 1/2 teaspoon salt in 1 cup of warm water. Swish and then spit it out, don't swallow.

  • Healthy adult or child with oral thrush can eat unsweetened yogurt (with live culture) or take acidophilus capsules or liquid. These are not fungicidal, but can help restore the normal oral bacterial flora.

  • Don't use OTC mouthwashes or sprays as they may alter normal oral flora. Mouthwashes with cetylpyridinium chloride have antifungal properties, but not in concentrations that would be effective against thrush.

2. OTC drug options:

  • Gentian Violet 1% (Schedule II - non-Rx, no public access)

    • Topical: Apply to affected area once or twice daily.

    • Solutions diluted to 0.25% to 0.5% may be less irritating. 

    • Apply with cotton-tipped applicator directly to affected area inside mouth.  Do not allow to be swallowed.

    • Not usually first line treatment.

      • Requires longer duration of treatment.

      • Messy - stains skin and clothing.

      • Associated with ulceration of mucosa.

3. Prescription Drug Option:

  • Nystatin Suspension 100,000 units/ml

  • Treatment option for mild disease (level 2 [mid-level] evidence)

  • Dosage

    • Children and adults: Swish and swallow 4 to 6 ml orally 4 times daily for 7 days minimum or 2 days after symptoms improve.  May extend treatment to 14 days if needed.

    • Infants: 1 or 2 ml 4 times daily - may use cotton swab or finger to apply.

  • Pregnancy: Safe for use during all trimesters.

  • Lactation: Compatible with breastfeeding. Poorly absorbed orally and does not enter breast milk.

Directions for use:

  • Adults and children: Swish, retain in mouth for as long as possible, up to a few minutes and swallow. Repeat this procedure 4 times daily.  

  • Infants: Place 100,000 units to 200,000 units (2ml) in each side of mouth 4 times a day. 
    Apply with a cotton swab or use a clean finger to sweep solution inside child's cheek.

  • Caution should be used when given to infants to avoid choking.

  • Advise to continue treating for at least 2 days after symptoms resolve to ensure successful outcome.

Assess Benefit

  • Follow up in 7 days
  • Onset of action: Symptomatic relief in 24 - 48 hours.

  • If significant improvement, but not full resolution, recommend continuing treatment for another 7 days (14 days total duration)
  • Refer to patient's primary care provider if unsuccessful after 14 days of treatment.

Adverse Effects:

  • Usually well tolerated.

  • Discontinue therapy if irritation or sensitization (rash, urticaria, contact dermatitis) occurs and refer to patient's primary care provider.

Detailed information on contraindications, cautions, adverse effects and interactions is available in individual drug monographs in the CPS (e-CPS), Lexi-Comp, AHFS, www.drugs.com or other reliable drug monograph references. For comprehensive drug comparisons, see RxFiles charts (www.rxfiles.ca). This information should be routinely consulted before prescribing.

Generic Name

Nystatin Oral Suspension

100,000 U/ML


  • pseudoDIN: 00951093
    • Max of 4 claims per 365 days per patient

  • May prescribe sufficient quantity to treat ONE episode of thrush, which is usually 7 days with a refill. 
    • If patient has had significant healing, but not full resolution after 7 days, may extend treatment to 14 days.  
    • Infants <1 year old will need approximately 56 mls for 7 days of treatment.
    • Children and adults will need approxiamtely 140mls for 7 days of treatment.
    • Each new episode of thrush is to be treated as a distinct episode and re-assessed.

  • Only products with an official indication from Health Canada for thrush and/or those recommended by reputable and reliable guidelines are considered for these guidelines.  Only the active ingredients in the "products" section are approved for pharmacist prescribing.
  • MedBroadcast Clinical Team. Oral thrush. C-Health.. http://chealth.canoe.com/condition_info_details.asp?channel_id=0&relation_id=0&disease_id=313&page_no=1.
  • Quail G. The painful mouth. Aust Fam Physician. 2008;37(11): 935-8. http://www.racgp.org.au/afp/200811/28197. Published November 2008.
  • Pappas PG, Kauffman CA, Andes D, et al. Clinical practice guidelines for the management of candidiasis: 2009 update by the infectious diseases society of America. Clin Infect Dis. 2009;48:503-35. doi:10.1086/599376.
  • Mayo Clinic Staff. Oral thrush. Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/oral-thrush/basics/definition/con-20022381. Updated August 12, 2014.
  • DynaMed. Oral candidiasis in children an adults. EBSCO Publishing. http://www.ebscohost.com/dynamed. Subscription required. Updated September 26, 2013.
  • Weisse ME. Candida. In: Kliegman RM, ed. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Elsevier Inc; 2007.
  • Pammi M. Clinical manifestation and diagnosis of Candida infection in neonates. UpToDate. http://www.uptodate.com. Subscription required. Updated September 8, 2015.
  • Sung DH. Oral Candidiasis. In: Repchinsky C, ed. Patient Self-Care. 2nd ed. Ottawa, ON: Canadian Pharmacists Association; 2010: 904-909.
  • Wlock K. Oral Candidiasis. In: Jovaisas B, ed. Compendium of Therapeutics for Minor Ailments. Ottawa, ON: Canadian Pharmacists Association; 2014: Available at https://www.e-therpeutics.ca. Subscription required.

No part of this work may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the copyright holder. For copyright permission requests, please contact druginfo@usask.ca.

Prepared by medSask
Reviewed by Dr. P Fourie, Family Physician; Dr. Yvonne Shevchuk, Professor, College of Pharmacy & Nutrition;
Dr. Brenda Schuster, PharmD
Funded by the Saskatchewan College of Pharmacy Professionals
Posted May 2010. Updated May 2017