Ingestion of Compost

Compost is biologically active material. As food breaks down, it changes chemically and microbiologically, which creates several possible risks.

 Toxicity 

Certain molds and bacteria that grow in compost produce toxins. Varies in severity and type. 

• Mycotoxins (from moldy food)
• Tremorgenic toxins (cause neurological signs)
• Botulinum toxin (rare but severe)

Severity: 

• Low-level exposure → GI upset
• Certain molds → neurological toxicity

Signs 

Mild: vomiting, diarrhea

Severe: tremors/shaking, seizures, disorientation, weakness or collapse

** Severe signs and /or persistent mild signs are an emergency and requires immediate veterinary care.

 Irritants 

Most compost ingestion causes GI irritation

Why?

• High bacterial load
• Fermentation by-products
• Acidic breakdown compounds

Common signs

• Vomiting
• Diarrhea
• Excess gas
• Abdominal discomfort

This is functional inflammation, not toxicity.

Allergens and immune triggers

• Degraded proteins
• Novel antigens
• Mold fragments

Mechanism: 

• Activate the immune system
• Increase mucus and inflammatory debris
• Worsen existing food or environmental allergies

Signs

• Soft stool or mucus
• Anal gland issues
• Ear or skin flare-ups days later

Digestive Bacterial overgrowth (not the same as outside infection)

Ingested bacteria usually do not infect rather they alter fermentation and gut balance

Results in:

• Strong odors
• Sour or metallic stool or anal gland smell
• Increased organic waste (excessive poop)

Severity in some dogs are more than others

Higher risk in dogs with undiagnosed or already existing:

• Sensitive digestion
• History of GI disease (IBD, pancreatitis)
• Allergies
• Small body size
• Large ingestion

How Compost causes digestive damage: 

Gut scarring :

• Severe untreated toxin exposure (constant exposure to toxin or left untreated)
• Chronic, repeated injury over time (constant irritation and gut shedding) 
• Ischemia or perforation -rare (Bones, excessive gas- Volvulus, worsening of digestive issues)

**Keep in mind the gut needs 3–5 days to regenerate in order to handle digestive work after it's been irritated. Even longer if pet has existing digestive medical condition. 

Acute gastrointestinal inflammation

• Vomiting
• Diarrhea
• Abdominal pain
• Mucus production

Liver stress 

• Ingestion of Mycotoxins 
• Large quantities are consumed
• Liver enzymes may elevate temporarily. However if they remain elevated can be an indicator of a deeper rooted issue. 
• May leave mild liver scarring depends on severity and other lifestyle factors. 

Pancreatic irritation

Triggered by:

• High-fat decomposing foods
• Fermentation by-products
• May cause transient pancreatitis-like signs
• May leave mild pancreatic scarring depends on severity and other lifestyle factors. 

** Dogs with prior pancreatitis are at higher risk

Temporary gut barrier disruption

• Increased permeability during inflammation
• Increased sloughing of intestinal cells

These Issues worsen and become long-term effects when 

• Repeated compost ingestion
• Severe toxin exposure
• Delayed treatment
• Pre-existing digestive or other digestive organ disease

When compost ingestion is an emergency (Immediate veterinary care):

• Tremors or seizures
• Severe lethargy
• Persistent vomiting
• Bloody diarrhea
• Collapse

Preventive takeaway for Responsible Pet Parenting !

• Compost should be secured
• Dogs should not access decomposing food
• Even “organic” scraps can be harmful once decomposed

Summary 

• Compost ingestion is usually an acute event
• Short-term effects are treatable and pets can recover
• Prompt care prevents complications and can protect the gut, liver, and pancreas
• Long-term damage should not be encouraged or turned into a norm

Resources

Center, S. A. (2014). Gastrointestinal disease. In R. W. Nelson & C. G. Couto (Eds.), Small animal internal medicine (5th ed., pp. 431–509). Elsevier Mosby.

DiBartola, S. P. (2020). Disorders of the gastrointestinal tract. In Fluid, electrolyte, and acid-base disorders in small animal practice (5th ed., pp. 455–512). Elsevier.

Hall, E. J., Simpson, K. W., & Williams, D. A. (2016). Diseases of the small intestine. In BSAVA manual of canine and feline gastroenterology (3rd ed., pp. 195–280). BSAVA.

Merck Veterinary Manual. (2024). Foreign bodies and obstruction of the gastrointestinal tract in small animals. Merck & Co., Inc.

Merck Veterinary Manual. (2024). Mycotoxicoses in animals. Merck & Co., Inc.

Plumb, D. C. (2023). Maropitant citrate. In Plumb’s veterinary drug handbook (10th ed.). Wiley-Blackwell.

Steiner, J. M., & Williams, D. A. (2017). Pancreatitis in dogs and cats. Veterinary Clinics of North America: Small Animal Practice, 47(4), 807–826. https://doi.org/10.1016/j.cvsm.2017.04.004

Washabau, R. J., & Day, M. J. (2013). Canine and feline gastroenterology. Elsevier Saunders

American College of Veterinary Emergency and Critical Care. (2022). Gastrointestinal foreign bodies and toxic ingestion in dogs.

ASPCA Animal Poison Control Center. (2024). Compost and mold toxicity in pets