Nocebo, from the maker of Placebo Maximum Strength, what sez:
Now for the first time, Nocebo is available for sale direct to the general public! Despite containing no active ingredients whatsoever, Nocebo can cause a wide range of undesirable effects, from nausea to diarrhea, that is because it’s potency lies entirely inside the human brain! Nocebo merely suggests that it is bad for you, your brain and body does the rest!
Buy it here for £5.99.