My boyfriend has found an ad on the internet for some strip of gel which is alleged to make women "wild with desire" as soon as they chew it. Is this really possible?

Certainly not. This is just a rip-off. Don't waste your money. At present, there is no drug which will immediately turn a woman on. If you're having problems in that area, consult a helpful woman doctor at a Family Planning Clinic. They're highly experienced in such matters.