Visine eyedrop trick.

The desire for revenge runs deep in all of us. Hence, many tricks were invented to fulfill those needs. The "Visine slipped into the drink" pay back carries additional appeal because it seems to offer an effective yet harmless form of revenge/pay back that could be easily administered even by the wimpiest of revenge seekers.Also, the mental image of an enemy sent hotfooting for the toilet is a hugely satisfying one.

The desirable effect.

What you'll need is just a few drops of visine and your victims drink. But, beware, the active ingredient in Visine eye drops is Tetrahydrozoline HCl 0.05%. Swallowing this substance can result in a number of nasty effects, including:

Lowering body temperature to dangerous levels
Making breathing difficult, or even halting it entirely
Blurring vision
Causing nausea and vomiting
Elevating and then dropping blood pressure
Causing seizures or tremors
Sending the victim into a coma.

One thing tetrahydrozoline has not been known to do is to cause sudden onset bouts of severe diarrhea. Although this belief has been around for decades, and everyone knows someone who knows someone who really did administer a Visine mickey to a deserving scum and thereby caused him an immediate serious case of the trots, there's no documented evidence the product would have that effect. Of the Visine poisoning cases studied by medical observers, we found none that mentioned diarrhea output brought about by the drug.

But then again, how far is all this true?

Hana Majid