Acemannan
Polydispersed beta-(1,4)-acetylated polymannose
Also known as: Acemannan Immunostimulant · CarraVet · Aloe vera extract · Polymannose
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Aid in treatment and management of fibrosarcoma | Recommended IP dose is 1 mg/kg. Recommended intralesional dose is 2 mg injected deep into each tumor mass. | IP / Intralesional | weekly | minimum of 6 treatments | 🌎 NA |
- Aid in treatment and management of fibrosarcoma: Prior to use, reconstitute with 10 mL sterile diluent. 5-10 mins may be necessary for complete dissolution. Shake well. Use within 4 hours. When used as a prelude to surgery, continue until delineation, necrosis or maximum tumor enlargement occurs (usually 2-4 weeks). Surgical excision recommended immediately upon delineation.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Aid in treatment and management of fibrosarcoma | Recommended IP dose is 1 mg/kg. Recommended intralesional dose is 2 mg injected deep into each tumor mass. | IP / Intralesional | weekly | minimum of 6 treatments | 🌎 NA |
- Aid in treatment and management of fibrosarcoma: Prior to use, reconstitute with 10 mL sterile diluent. 5-10 mins may be necessary for complete dissolution. Shake well. Use within 4 hours. When used as a prelude to surgery, continue until delineation, necrosis or maximum tumor enlargement occurs (usually 2-4 weeks). Surgical excision recommended immediately upon delineation.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Acemannan is a water-soluble, complex carbohydrate polymer derived from Aloe vera. It is utilized in veterinary medicine primarily as a non-specific immunostimulant.
- Primary Labeled Use: Aid in the surgical treatment and clinical management of fibrosarcomas in dogs and cats.
- Off-label/Investigational Uses: Has been tried for viral infections in cats (FeLV, FIV, FIP) and papillomatosis in dogs.
- Clinical Controversy: Its systemic use remains controversial due to a lack of robust, controlled clinical studies supporting its efficacy in veterinary medicine.
- Topical Use: Topical formulations are available and may potentially reduce wound healing time.
Mechanism of action
Acemannan functions as a non-specific immune system modulator.
- Cytokine Induction: Induces increases in key pro-inflammatory and immunomodulatory cytokines, specifically Tumor Necrosis Factor-alpha (TNF-α), Interferon, and Interleukin-1 (IL-1).
- Cellular Response: → Leads to increased lymphocytic infiltration and accumulation at injection sites, promoting a localized immune response against tumor cells or pathogens.
- Antiviral Activity: Has demonstrated the ability to suppress HIV replication in tissue cultures, though in vivo antiviral efficacy in veterinary species remains unproven.
Safety & warnings
Contraindications
- Patients with demonstrated past severe hypersensitivity reactions to acemannan
Adverse effects
- Hypersensitivity reactions
- Localized necrosis at injection sites
- Hyperactivity
- Lethargy
- Fever
- Hypotension
- Salivation (with IV bolus)
- Weakness and collapse (with IV bolus)
- Tachycardia and tachypnea (with IV bolus)
- Prolonged pain or bleeding at intralesional injection sites
- Monocyte infiltrates on peritoneal surfaces, liver, lung, and spleen (with IP injection)
- Abdominal pain, diarrhea, and vomiting (with high-dose IP injection)
Precautions
Important Warning: Bolus IV administration can cause severe systemic reactions including salivation, weakness, collapse, hypotension, tachycardia, and tachypnea.
- Intraperitoneal (IP) Use: Can cause monocyte infiltrates on peritoneal surfaces and abdominal organs, potentially leading to abdominal pain, vomiting, and diarrhea at high doses.
- Pregnancy/Nursing: Safety has not been established in pregnant or nursing animals, though its chemical nature suggests it is unlikely to be a teratogen.
Monitoring
- Clinical efficacy (tumor delineation, necrosis, or reduction)
- Adverse effects (especially localized injection site reactions, hypersensitivity, or systemic signs if given IV/IP)
Overdose
Acemannan appears to have a wide margin of safety regarding acute toxicity.
- Dogs (IP): Single IP injections of 50 mg/kg resulted in no significant signs of toxicity.
- Dogs (Oral): Acemannan fed orally at rates of up to 1.5 g/kg/day for 90 days showed no significant adverse effects.
Available products
Formulations
- Injection: 10 mg vial (with 10 mL sterile saline diluent)
- Topical wound dressing
- Topical cleansing foam
Veterinary
- Acemannan Immunostimulant® (VPL): 10 mg vial with 10 mL vial of diluent (sterile saline)
- CarraVet® (VPL): Topical wound dressing and cleansing foam
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at temperatures less than 35°C (95°F); protect from extremes of heat or light. Reconstituted injectable solutions must be used within 4 hours after rehydration.
Client information
Veterinary Use Only: This compound is recommended for use by veterinary professionals only.
- Investigational Nature: Pet owners should be made aware of the 'investigational' nature of using acemannan systemically, especially for off-label viral treatments.
- Potential Reactions: Adverse effects are possible, including pain or swelling at the injection site, lethargy, or gastrointestinal upset. Report any severe lethargy, collapse, or breathing difficulties to the veterinarian immediately.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.