MHRA Strengthens Botulinum Toxin Warnings After Rare Botulism Cases

Patients receiving botulinum toxin injections have been warned to seek immediate medical help if they develop swallowing, speech or breathing problems, as Britain’s medicines regulator strengthens safety information across all authorised type A products.

The Medicines and Healthcare products Regulatory Agency has ordered stronger warnings for all botulinum toxin type A products after reports of rare but potentially life-threatening cases of botulism linked to medical and cosmetic treatments.

The updated MHRA botulinum toxin warnings, announced on 15 July 2026, will appear in product information and patient leaflets across the UK. They will explicitly highlight the risk of iatrogenic botulism, which occurs when the effects of the toxin spread beyond the area where it was injected.

Patients have been told to seek emergency medical assistance if they experience difficulty swallowing, slurred speech, breathing problems, muscle weakness or severe drooping of the upper eyelids after treatment.

Symptoms usually appear between four and eight days after an injection but can take up to four weeks to develop. Severe cases can require intensive care and mechanical ventilation.

Botulinum toxin type A is a prescription-only medicine used for cosmetic procedures and several medical conditions, including chronic migraine, muscle spasms, excessive underarm sweating and an overactive bladder.

Warnings to Be Added Across Authorised Products

The MHRA said serious reactions caused by the distant spread of the toxin have been monitored and reflected in product information since 2007. However, the wording will now be strengthened across every UK-authorised botulinum toxin type A product over the coming months.

Healthcare professionals have been instructed to explain the symptoms to new and existing patients, check that products are authorised for UK use and follow the dosing and administration instructions for the individual medicine.

The units used to measure different botulinum toxin products are not interchangeable, meaning a dose associated with one brand cannot automatically be applied to another.

The regulator said the risk of a serious reaction may be higher when large doses are administered, a product is injected into an unapproved site or treatment is used outside its licensed indications.

Patients with neurological disorders, previous swallowing difficulties or a history of aspiration may also face an increased risk.

Dr Alison Cave, the MHRA’s chief safety officer, said the treatments were effective when used correctly but stressed that patients and professionals must act quickly if symptoms of botulism appear because the condition is a medical emergency.

Regulator Warns Against Unlicensed Injections

The new safety action also renews warnings about counterfeit and unauthorised products obtained outside regulated supply chains.

The MHRA’s Criminal Enforcement Unit opened investigations after a rise in hospital admissions linked to suspected unlicensed botulinum toxin products in 2025. England recorded 41 confirmed botulism cases between 4 June and 6 August that year across the North East, East Midlands, East of England, North West and Yorkshire and Humber. London was not among the regions identified in that outbreak.

More than 4,700 vials of unlicensed botulinum toxin were seized by the MHRA and Border Force between May 2023 and August 2025. Officials found evidence of injections being offered in homes, hair salons and through mobile beauty services, often after being promoted on social media at unusually low prices.

The nationwide warning nevertheless applies to patients and practitioners across London. People considering cosmetic injections should check that the practitioner is appropriately trained and qualified, that a consultation and valid prescription have been provided, and that the product is licensed in the UK.

The MHRA advises patients to ask to see the packaging and product details before treatment. Suspected side effects can be reported through the Yellow Card scheme, but making a report should not delay emergency care.

The regulator will introduce the revised leaflets and professional information over the coming months while continuing to monitor reported reactions and investigate the illegal supply of botulinum toxin products.