FOI release

Adverse and Allergic Reactions Associated with Botulinum Toxin Products

Case reference FOI2026/01094

Received 19 September 2026

Published 6 November 2026

Request

I am writing to make a Freedom of Information request regarding adverse reactions, specifically allergic and hypersensitivity reactions, associated with botulinum toxin products used in the UK. I would like the MHRA to provide the most complete and up-to-date data held by the agency, preferably from the Yellow Card reporting system and any other relevant pharmacovigilance databases. Please provide the following: The total number of UK Yellow Card reports associated with botulinum toxin products, broken down by individual product/brand where possible (for example, Botox/Vistabel, Azzalure, Bocouture, Nuceiva and other authorised botulinum toxin products). Of these reports, the number specifically classified or coded as: • allergic reaction • hypersensitivity • anaphylaxis • anaphylactic shock • angioedema • urticaria/hives •facial swelling • swelling of the lips, tongue or throat bronchospasm or breathing difficulty where recorded as an allergic/hypersensitivity reaction other suspected immune-mediated reactions. Please provide the number of reports involving serious reactions, including those resulting in: hospitalisation emergency treatment life-threatening events intensive care admission disability death. Please provide the data broken down by: botulinum toxin product/brand & year of report. therapeutic versus cosmetic use, where this information is available age group, where disclosure is possible. sex, where disclosure is possible. Please provide the number of reports where the reaction occurred after a cosmetic administration of botulinum toxin. Please provide any data held by the MHRA concerning suspected allergic or hypersensitivity reactions following repeat exposure to botulinum toxin, including cases where the individual had previously received the same or another botulinum toxin product without an apparent reaction. Please state whether the MHRA holds information concerning the time between administration of botulinum toxin and onset of an allergic or hypersensitivity reaction. If so, please provide aggregated data showing the reported time to onset. Please provide the number of reports in which the botulinum toxin product was considered the suspected medicine, as opposed to a concomitant medicine or another suspected cause. Please provide any information held regarding the number of these reports that were subsequently assessed by the MHRA as potentially related to the botulinum toxin product. Please provide the reporting period covered by the data and the date on which the data were extracted. I would also like clarification regarding under-reporting. The MHRA has previously stated that Yellow Card reporting is a spontaneous reporting system and that the indication for use is not necessarily recorded on every report. I would therefore like to know: • Whether the MHRA has made any assessment of the likely level of under-reporting of allergic or hypersensitivity reactions to botulinum toxin. • Whether the MHRA has any estimated figures for the true number of allergic reactions compared with the number reported through Yellow Card. • Whether the MHRA has identified any particular limitations in using Yellow Card data to establish the incidence or prevalence of allergic reactions to cosmetic botulinum toxin. Please provide the information electronically, preferably in spreadsheet/CSV format where possible. I am specifically requesting aggregated statistical information and am not requesting personal information relating to individual patients. If any part of this request is considered exempt from disclosure, please provide the remainder of the information and identify the specific exemption being relied upon. I would also be grateful if you could distinguish between: (a) the number of reports received, (b) the number of individual suspected reactions/events recorded within those reports, and (c) any cases that have subsequently been medically assessed or investigated by the MHRA. I understand that a Yellow Card report represents a suspected adverse reaction and does not necessarily establish that the medicine caused the reaction. I am therefore requesting the underlying reported data and any available MHRA assessment rather than assuming causation. Please treat this correspondence as a formal Freedom of Information request.

Response

See attached

Documents

• FOI2026.01094 Annex 1.pdf (86.7 KB)
• FOI2026_01094 (redacted).pdf (2.7 MB)

This is Medicines and Healthcare products Regulatory Agency's response to a freedom of information (FOI) or environmental information regulations (EIR) request.

You can browse our other responses or make a new FOI request.