A common Israeli army urban legend -- the addition of saltpeter, drinking soda or bromide to the soldiers' food, supposedly to decrease their sexual drive, so that their minds would be occupied with the right things. Many people firmly believe this is done - and it might really work as a placebo pill for them.

This legend was covered by the Israeli movie Sababa (1983; a chapter of the Lemon Popsicle series), where one of the soldiers, who worked as the cook, was instructed to add extra "soda" (meaning saltpeter or drinking soda?) to the meals that day, since the blonde Swedish ambassador who arrived for a visit was too much on the soldiers' minds. Rather than decreasing the sexual drive, the soda was supposed to temporarily render the guys sexually impotent.

Since then, the legend hasn't lost any of its relevance and is happily told from one generation of recruits to the next. So far I haven't found any reliable evidence of such effects induced by any of those substances, much less about the IDF employing them.

P.S. In my basic training, some guys kept claiming "they" are adding something to our food, blaming the lack of morning erection on it. I think it was simply caused by the increased mental pressure one's undergoing in basic training.

P.P.S. According to Apatrix, this same urban legend is widespread in the Greek Armed Forces too.