The UK Medicines Information list of common medicines excipients which cause problems includes lactose and wheat-derived gluten (maize and corn starch do not cause coeliac disease).²⁷

Refined peanut/arachis oil is considered to be of low or minimal risk for the vast majority of people allergic to peanuts. However, unrefined arachis or nut oils have a greater chance of proteins remaining in the oil.¹⁶ UKMi advises that pharmaceutical grade arachis oil is of low risk, but patients affected by peanut allergies "may prefer to avoid it and it is easy to do so."²⁷

Eggs are used in the preparation of some vaccines, and allergenic proteins such
as ovalbumin may be present in influenza vaccines, injections, and the Fluenz nasal spray. Hypersensitivity to eggs or chicken proteins is also a contraindication for yellow fever vaccine.²⁸

Pork-derived gelatin occurs as a stabiliser in a number of vaccines, and can be a common cause of allergic reactions to vaccines.⁸ Concerns have been raised about allergens in the MMR vaccine, but studies have shown that "anaphylactic reactions to MMR vaccine are not associated with hypersensitivity to egg antigens but to other components of the vaccine (such as gelatin)."

Public Health England's "Green Book" advice on immunisations says children with egg allergy should receive the MMR vaccination as a routine procedure in primary care.²⁹

Known sensitivity to honey may prevent the use of honey dressings in woundcare.³⁰ Food allergies should also be a consideration with dietary supplements. Reports of a probable allergy to glucosamine chondroitin sulphate because of a shellfish allergy have led to manufacturers including a warning about the potential reaction.

However, a small study in 2006 found no specific IgE reactions to glucosamine, suggesting the allergen potential from crushed shellfish was not clinically relevant.³¹