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An unexpected allergic skin reaction to peppermint oil capsules
  1. Gabrielle Sanders
  1. Obstetrics and Gynaecology, Colchester Hospital, East Suffolk and North Essex NHS Foundation Trust, Colchester, UK
  1. Correspondence to Dr Gabrielle Sanders; gabriellesanders01{at}


Peppermint oil capsules are prescribed to manage abdominal colic and distension, a common complaint in postcaesarean section patients. Arachis (peanut) oil is contained within one frequently prescribed peppermint formulation: Colpermin. This ingredient is contraindicated in patients with peanut and soya allergy; however, this is not stated in the side effects or contraindications section of the British National Formulary, or present on the medication packaging. A postpartum woman in her early 30s had an unexpected allergic reaction to the capsules, in the form of a generalised body rash, fortunately with no anaphylactic features. The patient reported the same reaction to soya in the past. After review of the patient’s clinical and medication history, Colpermin capsules were thought to be responsible for the patient’s symptoms. This case highlights the necessity for clearer documentation in prescribing formularies and on medication packaging to ensure patient safety.

  • Contraindications and precautions
  • General guidance on prescribing
  • Obstetrics, gynaecology and fertility
  • Drugs: gastrointestinal system
  • Drugs: obstetrics and gynaecology

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  • Contributors GS confirms that GS is sole author of this case report and received no assistance with writing. GS was the junior doctor in this case which responded to the patients rash and identified the underlying cause.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.