Nasal discharge in dogs ranges from normal post-exercise clear fluid to bloody or one-sided discharge that signals a serious problem like a fungal infection, foreign body, or nasal tumor. The color, consistency, and whether it comes from one or both nostrils are the key factors that determine urgency.
Last reviewed: June 2026
What Does Nasal Discharge Color Mean in Dogs?
Not all nasal discharge is created equal. The character of the discharge guides how urgently a vet evaluation is needed.
Clear, watery discharge from both nostrils is often normal — dogs produce thin nasal secretions during exercise, in cold air, or when excited. Short-lived clear discharge is generally not alarming.
White or cloudy discharge suggests mucus production but is still often benign, especially in both nostrils after a kennel cough infection or mild upper respiratory illness.
Yellow or green discharge indicates bacterial infection or significant inflammation. This can follow a viral URI (like parainfluenza), be a sign of bacterial rhinosinusitis, or point to a foreign body that has become infected.
Bloody discharge (epistaxis) is always worth a vet call. It can come from trauma, severe nasal infections (particularly Aspergillus fungal rhinitis), nasal tumors, a foreign body, or systemic clotting disorders. One-sided nosebleeds in a middle-aged to older dog are particularly concerning for a nasal tumor.
One-sided discharge — regardless of color — is a red flag. Bilateral (both nostrils) discharge typically suggests systemic infections or respiratory viruses. One-sided discharge points toward something affecting only one side: a foreign body, nasal polyp, dental root abscess communicating with the nasal passage, or tumor.
Common Causes of Dog Nasal Discharge
Upper respiratory infections are the most common cause of sudden-onset bilateral discharge in dogs. Canine infectious respiratory disease complex (kennel cough) involves multiple pathogens — Bordetella bronchiseptica, canine parainfluenza, and others — and produces coughing, sneezing, and nasal discharge. The AAHA Canine Vaccination Guidelines, 2022 include Bordetella vaccination as a lifestyle-based recommendation, particularly for dogs in boarding, daycare, or dog park settings.
Nasal foreign bodies — grass awns, foxtails, plant material — commonly cause sudden, intense, one-sided sneezing and discharge. The dog may paw at its nose repeatedly. This is an urgent situation; foreign material migrates and can cause deep tissue infection.
Aspergillus rhinitis is a fungal infection of the nasal passages that produces a depigmented, ulcerated nasal planum, bloody or mucopurulent discharge (often one-sided), and sometimes visible discharge on the inside of the nostril. It is more common in dolichocephalic (long-nosed) breeds. Diagnosis requires rhinoscopy and fungal culture or serology; treatment is intranasal antifungal therapy (clotrimazole infusion).
Nasal tumors (most commonly adenocarcinoma, squamous cell carcinoma) are progressive causes of one-sided discharge, nosebleeds, facial deformity, and sneezing in middle-aged to older dogs. Diagnosis requires CT scan and biopsy. Prognosis is guarded to poor without radiation therapy.
Dental disease — particularly root abscesses of the upper carnassial tooth — can erode into the nasal passages, causing nasal discharge that appears to come from the nose but originates from a periapical abscess. Dogs may also have facial swelling below the eye.
When to See a Vet
Call your vet today if:
- Discharge is yellow, green, or has blood in it
- Discharge comes from only one nostril
- Your dog is pawing at its nose repeatedly
- Sneezing is intense and sudden after outdoor activity (possible foreign body)
- Discharge has been present for more than 5–7 days
Go to the ER immediately if:
- Your dog has significant, ongoing nosebleed that won't stop
- Gums are pale or your dog appears weak alongside the nosebleed
- Your dog has difficulty breathing through its nose and is in distress
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Frequently Asked Questions
Is it normal for a dog's nose to be runny? A small amount of clear, watery discharge from both nostrils is normal — dogs produce nasal secretions during exercise, in cold air, or after sniffing. Discharge that is colored, one-sided, persistent, or accompanied by sneezing or pawing at the nose is not normal and warrants evaluation.
Why does my dog have yellow discharge from one nostril? One-sided yellow or green discharge is one of the most concerning presentations — it suggests a localized problem on that side: a foreign body, dental abscess communicating with the nasal passage, nasal polyp, fungal infection, or nasal tumor. This needs same-day or next-day evaluation, not a wait-and-see approach.
Can nasal discharge in dogs be a sign of cancer? Yes. Nasal tumors are a recognized cause of progressive, one-sided discharge, nosebleeds, and facial swelling — particularly in middle-aged to older dogs and in long-nosed breeds like Collies and Retrievers. A CT scan and biopsy are needed for diagnosis. If your dog has one-sided discharge and is over 7 years old, mention this concern to your vet.
How much does diagnosing nasal discharge cost? A basic exam runs $50–150. Skull or chest radiographs add $150–400. CT scan of the nasal cavity (gold standard for nasal disease) costs $800–2,000 with anesthesia. Rhinoscopy with biopsy adds $500–1,200. Fungal serology or cultures run $100–300. Foreign body removal via rhinoscopy is $600–1,500.
What home care can I do for mild nasal discharge? For mild, clear, bilateral discharge in an otherwise healthy dog, use a humidifier to keep air moist, keep the area around the nostrils clean with a damp cloth, and monitor for any change in character. Do not use human nasal sprays or decongestants in dogs — many are toxic. If signs persist more than a week or worsen, see a vet.
Still Not Sure if Your Dog Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of your dog's nasal discharge and nose, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.