I suffer from a rare neurological condition that does not respond to painkillers - not even morphine. What is required is a vasoconstricter. I belong to a help group and it's well known amongs us that the combination of caffiene and taurine in redbull (or other energy drinks)will constrict the arteries to a small degree, thus giving us some relief. Very handy when we've run out of our injections. And as it's a neurological condition it's understandable that it would work for headaches too, which are often caused by dilated arteries.

I have always used tesco or asda  headache tablets at about 48p for 16. They have exactly the same ingredients as Anadin extra. I also use asda's own antacid as it's the same as gaviscon, but about a quarter of the price.

I can understand the problem if someone has allergies though.