What you need to know
Gastrointestinal (GI) problems are among the most common reasons pet owners visit the veterinarian. Some digestive symptoms are mild and self-limiting — a brief bout of soft stool after a dietary indiscretion, for example. Others can signal chronic conditions, infections, or emergencies that require prompt medical attention.
The challenge for most pet owners is knowing the difference. Dogs and cats cannot tell you what hurts. They communicate through behavioral changes, appetite shifts, and changes in their stool — signals that are easy to miss or dismiss as "normal."
This guide is designed to help you recognize the most common signs of digestive distress, understand what they may indicate, and know when to contact your veterinarian.
Common signs of digestive issues
Veterinary gastroenterology literature identifies several key indicators that something may be off in your pet's digestive system:
- Changes in stool consistency — Persistent soft stool, diarrhea, mucus-coated stool, or unusually hard/dry stool
- Vomiting — Occasional regurgitation may be benign, but repeated vomiting (especially with bile, blood, or undigested food hours after eating) warrants evaluation
- Changes in appetite — Eating significantly more or less than usual, or suddenly refusing food they normally enjoy
- Excessive gas or bloating — Some gas is normal, but persistent flatulence or visible abdominal distension is not
- Weight changes — Unexplained weight loss is particularly concerning and may indicate malabsorption or chronic disease
- Grass eating — While the reason dogs eat grass is debated, increased or frantic grass eating is sometimes associated with nausea
- Scooting or licking — Excessive licking of the anal area or scooting may indicate irritation, though anal gland issues should also be ruled out
- Lethargy — A pet that is unusually tired, withdrawn, or reluctant to play may be experiencing GI discomfort
- Changes in coat quality — A dull, dry, or thinning coat can sometimes reflect poor nutrient absorption
What these signs may indicate
It's important to understand that these symptoms are not diagnoses — they are signals. The same symptom can result from many different underlying causes. Chronic diarrhea in a dog, for example, could reflect anything from a dietary sensitivity to inflammatory bowel disease to a parasitic infection.
Common conditions associated with persistent GI symptoms include:
- Dietary indiscretion — Eating something inappropriate (garbage, table scraps, foreign objects)
- Food sensitivities or intolerances — Reactions to specific proteins or ingredients
- Parasitic infections — Giardia, roundworms, hookworms, and others
- Inflammatory bowel disease (IBD) — Chronic inflammation of the intestinal lining
- Pancreatitis — Inflammation of the pancreas, which affects digestion
- Exocrine pancreatic insufficiency (EPI) — Insufficient production of digestive enzymes
- Dysbiosis — Imbalance in the gut microbiome
- Stress-related GI issues — Anxiety, changes in routine, or environmental stressors
Not every change in stool or appetite requires a vet visit. Mild, self-resolving episodes that last less than 24 hours — particularly with an obvious cause (a new treat, mild stress) — may not require medical attention. However, any symptom that persists beyond 48 hours, recurs frequently, or is accompanied by lethargy, blood, or significant behavioral change should be evaluated professionally.
Stool as a diagnostic tool
Veterinarians often ask about stool quality because it provides meaningful information about digestive function. The Purina Fecal Scoring System is a widely used 7-point scale:
- Score 1 — Very hard, dry pellets (may indicate dehydration or insufficient fiber)
- Score 2–3 — Firm, segmented, holds shape (generally considered ideal)
- Score 4 — Soft but formed, loses shape when picked up
- Score 5 — Very soft, mostly shapeless
- Score 6–7 — Watery, no texture (diarrhea — warrants veterinary attention if persistent)
Recording your pet's stool consistency, frequency, color, and any unusual features (mucus, blood, undigested food) can provide valuable information for your veterinarian.
When it's different in cats
Cats tend to hide illness more effectively than dogs, making GI symptoms easier to miss. Specific signs to monitor in cats include:
- Vomiting hairballs more than once or twice per month (this may not be "normal")
- Changes in litter box habits — frequency, consistency, or straining
- Weight loss despite a normal or increased appetite
- Decreased grooming or changes in coat quality
- Hiding or withdrawal from social interaction
Research published in the Journal of Feline Medicine and Surgery notes that chronic vomiting in cats is often accepted by owners as normal when it may actually warrant diagnostic investigation.
Practical recommendations
- Keep a symptom log — Track what your pet eats, stool quality, vomiting episodes, energy level, and any behavioral changes. Bring this log to vet appointments
- Photograph stool changes — As unpleasant as it sounds, a photo of abnormal stool gives your vet immediate visual information
- Note timing and triggers — Did symptoms start after a food change? A stressful event? A new medication? Context matters
- Don't self-diagnose or self-treat — Over-the-counter remedies and dietary changes made without veterinary guidance can mask symptoms and delay diagnosis
- Monitor hydration — Offer fresh water and monitor intake, especially during vomiting or diarrhea episodes
When to contact your veterinarian
- Diarrhea or vomiting persists beyond 48 hours
- You see blood (red or dark/tarry) in vomit or stool
- Your pet stops eating for more than 24 hours
- Your pet appears lethargic, weak, or in pain
- There is visible abdominal bloating or distension
- Your pet is a puppy, kitten, senior, or has a pre-existing condition
- Symptoms recur frequently even if each episode resolves
Common myths
Myth: "Dogs vomit all the time — it's normal"
Occasional vomiting can happen, but frequent vomiting is not normal in healthy dogs. A dog that vomits weekly or more should be evaluated by a veterinarian. Chronic vomiting can indicate gastritis, food intolerance, pancreatitis, or other conditions.
Myth: "Cats always throw up hairballs — that's just what cats do"
While hairballs occasionally occur, frequent vomiting in cats — even when hair is present — may indicate an underlying GI condition. The American Association of Feline Practitioners recommends investigation if vomiting occurs more than twice monthly.
Myth: "Soft stool means my pet needs more fiber"
Fiber can sometimes help firm up stool, but chronic soft stool has many possible causes. Adding fiber without addressing the underlying issue may delay a proper diagnosis. Discuss dietary changes with your veterinarian first.
- GI symptoms are among the most common reasons for veterinary visits in dogs and cats
- Key signs include changes in stool, appetite, weight, energy level, and coat quality
- Symptoms are signals, not diagnoses — the same symptom can have many different causes
- Cats tend to hide GI discomfort, making symptoms easier to miss
- Keep a symptom log and photograph abnormal stool — this information is valuable for your vet
- Any symptom that persists beyond 48 hours, involves blood, or includes lethargy should be evaluated