I was offered almost every gut medication going, but never cromolyn. This old mast cell stabiliser, which evolved from a medicinal herb, has made a huge difference to my MCAS gut symptoms. Here’s its history, how it works, why it’s so rarely prescribed in the UK, where people get it, and how I started low and slow.

DAO is the enzyme that breaks down histamine from food. For people with MCAS, taking it before meals can mean fewer reactions, especially when eating out or eating histamine-rich foods. Here’s how it helps, what it can’t do, and how nine UK DAO supplements compare on price and ingredients.