Bismuth Subsalicylate: veterinary dose and monograph

At a glance

Drug class

Gastrointestinal

Also known as

Pepto-Bismol, BSS, Pink bismuth

Species with doses

Dogs, Cats, Cattle, Horses, Pigs and Ferrets

Routes

PO

Last reviewed

1 October 2026

Indications

• Acute, uncomplicated diarrhoea / gastroenteritis (short-term, dogs)
• Gastritis / mild gastric irritation (mucosal protection)
• Helicobacter-associated gastritis (component of triple therapy)

Bismuth Subsalicylate dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Acute diarrhoea / gastritis (short term): Plumb’s p.153: 1 mL per 5 kg PO three times daily for no more than 5 days (Hall & Simpson); 0.25 mL/kg q4–6h up to 2 mL/kg q6–8h (Cote); uraemic gastritis 2 mL/kg q6–8h (Bartges). Papich 5e: 1–3 mL/kg/day in divided doses. Blackens stools; radio-opaque.
• Helicobacter gastritis (triple therapy): Plumb’s p.153 (Hall 2000): metronidazole 15.4 mg/kg q8h + amoxicillin 11 mg/kg q8h + bismuth 0.22 mL/kg q4–6h for 3 weeks. Alternative (Leib 2007): 262 mg tablets q12h by weight (<5 kg ¼; 5–9.9 kg ½; 10–24.9 kg 1; >25 kg 2 tablets) with metronidazole 10 mg/kg and amoxicillin 15 mg/kg q12h for 2 weeks.

Cats

• Diarrhoea (short term, caution): Plumb’s p.153: 0.5–1 mL/kg q12h for 3 days (Scherk); 0.25 mL/kg q4–6h (Cote). Cats are salicylate-sensitive — avoid frequent or high doses and other salicylates/NSAIDs. Papich 5e (dogs and cats): 1–3 mL/kg/day divided.

Cattle

• Calf diarrhoea: Papich 5e: 30 mL per calf q30min for 8 doses. Plumb’s p.153: 60 mL two to four times daily for 2 days (Corrective Mixture label); adults 2–3 oz PO 2–4 times daily (Braun). Follow the product label withdrawal.

Horses

• Diarrhoea (foals / adults): Papich 5e: 1–2 mL/kg q6–8h PO. Plumb’s p.153: foals 3–4 oz (90–120 mL) per 45 kg PO q6–8h (Madigan); 1 oz per 8 kg 3–4 times daily (Clark & Becht).

Pigs

• Baby-pig diarrhoea: Plumb’s p.153 (Corrective Mixture label). Follow the product label withdrawal.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Calf diarrhoea: Papich 5e: 30 mL per calf q30min for 8 doses. Plumb’s p.153: 60 mL two to four times daily for 2 days (Corrective Mixture label); adults 2–3 oz PO 2–4 times daily (Braun). Follow the product label withdrawal.

Ferrets

• Helicobacter mustelae (triple therapy): Plumb’s p.153: bismuth subsalicylate 17.5 mg/kg PO q8h with metronidazole 20 mg/kg and amoxicillin 20 mg/kg q12h for 21 days, plus famotidine and sucralfate (Johnson 2006); or 7.5 mg/kg with metronidazole 20 mg/kg and amoxicillin 30 mg/kg, all q8h for 3–4 weeks (Johnson-Delaney 2009).

Contraindications

Cats (salicylate sensitivity — avoid or use only with great caution). Concurrent NSAIDs/aspirin or bleeding disorders (additive salicylate/GI effects). Suspected GI perforation. Before abdominal radiographs (radio-opaque). Renal impairment. Known salicylate hypersensitivity.

Species-specific warnings

Cats: Contains salicylate — cats metabolise salicylates poorly; avoid bismuth subsalicylate (toxicity risk). Use cat-appropriate antidiarrhoeals instead.

Adverse effects

• Black/grey discolouration of stool (mimics melaena) and sometimes the tongue
• Constipation; salicylate effects with overuse
• Radio-opacity (confounds radiographs)
• Salicylate toxicity in cats / with overdose

Drug interactions

• NSAIDs/aspirin: additive salicylate effects (GI/bleeding)
• Tetracyclines/fluoroquinolones: bismuth chelation reduces their absorption — separate dosing
• Anticoagulants: salicylate may potentiate bleeding
• Drugs requiring acid/absorption: altered by coating

Pregnancy and lactation

Avoid (salicylate); use other antidiarrhoeals if needed in pregnancy.

Monitoring

• Diarrhoea resolution (short-term use only — reassess if not improving in a few days)
• Distinguish drug-induced black stool from true melaena
• Avoid before planned abdominal radiographs
• Salicylate effects with overuse / never in cats

Toxicity and overdose

Short-term canine use is well tolerated apart from black stools/constipation. Overuse or use in cats can cause SALICYLATE toxicity (vomiting, acid–base/electrolyte disturbance, hyperthermia, CNS signs). The black stool can mask or be mistaken for true GI bleeding (melaena) — a diagnostic pitfall.

Management: For salicylate toxicity: discontinue, supportive care, IV fluids, correct acid–base/electrolytes, and standard salicylate-toxicosis management. Decontaminate large recent ingestions. Distinguish drug-related black stool from genuine melaena.

Clinical pearls

• A short-term OTC fix for acute canine diarrhoea/gastritis — coats the gut, binds toxins, and reduces secretion
• AVOID in cats (salicylate) and don't stack with NSAIDs/aspirin
• Warn owners stools turn BLACK (and it's radio-opaque) — don't mistake it for melaena or let it confound radiographs
• Separate from tetracyclines/fluoroquinolones (bismuth chelation) and limit to a few days

Mechanism of action

In the gut, bismuth subsalicylate dissociates into bismuth (which coats/protects the mucosa, binds bacterial toxins, and has mild antibacterial action — including against Helicobacter) and salicylate (which inhibits prostaglandin synthesis, reducing intestinal secretion and inflammation — the antisecretory antidiarrhoeal effect). The bismuth reacts with luminal sulphur to form black bismuth sulphide, explaining the dark stool.

Formulations and products

• Oral suspension ~17.5 mg/mL (262 mg/15 mL)
• 262 mg chewable tablet
• Pepto-Bismol — 262 mg/15 mL suspension; 262 mg chewable, Suspension / chewable (human-label)

Storage

Suspension/tablets: 15–30 °C; shake suspension. Note it darkens stool and is radio-opaque.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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• Activated Charcoal
• Apomorphine
• Capromorelin
• Cimetidine
• Cisapride
• Famotidine
• Hyoscine Butylbromide (N-Butylscopolammonium)
• Lactulose

Frequently asked questions