'Inactive' ingredients in most pills may cause allergic reactions: Study

A vast majority of the most frequently prescribed medications contain at least one ingredient capable of causing an adverse allergic reaction, a US study has found.

Known as inactive ingredients, these components are added to improve the taste, shelf-life, absorption and other characteristics of a pill, but the researchers found that more than 90 per cent of all oral medications tested contained at least one ingredient that can cause allergic or gastrointestinal symptoms in sensitive individuals.

Such ingredients include lactose, peanut oil, gluten and chemical dyes, scientists said.

"When you're a clinician, the last thing you want to do is prescribe a medication that could cause an adverse reaction or allergic reaction in a patient," said C Giovanni Traverso, from Massachusetts Institute of Technology (MIT).

"This project was inspired by a real-life incident where a patient with Celiac disease was prescribed a medication and the formulation of the pill they picked up from the ...