It first circulated in the United States at the end of last year. It then appeared in South Africa, starting in Cape Town, before dying down and now resurfacing again in KwaZulu-Natal.
It's one of those dreaded emails engineered to scare the daylights out of you - in this case young women - which upon investigation turns out to be a hoax.
The email, supposedly from the department of medicine at Tygerberg Hospital, Cape Town, warns of a new date rape drug called Progesterex.
According to the email, it is essentially a small sterilisation pill now being used by rapists at parties and clubs to rape and sterilise their victims.
Like the date rape drug Rohypnol, it is supposedly surreptitiously dropped into the drink of an unsuspecting victim, who then loses all memory of the next 24 hours.
The email says: "Progesterex is being used in conjunction with Rohypnol so that the woman doesn't conceive from the rape and the rapist doesn't have to worry about a paternity test identifying him.
"But the drug's effects aren't temporary. Progesterex was designed to sterilise horses and any woman who takes it will be sterilised for life. Veterinary schools at any hospital have access to the drug and it's about to break out big on local campuses."
However, young women can relax. There is no medicine anywhere called Progesterex, say the experts.
The Medicine Information Centre in Cape Town told The Mercury that "there is no product registered under this name in South Africa", and second, there was no known drug anywhere that could cause sterilisation on humans and animals like this.
"We spent a lot of time and energy researching Progesterex when we first heard about it," said a spokesman, "but it definitely doesn't exist.
"We also liaised closely with the vets at Ondestepoort in Pretoria, who said it was completely improbable."
According to the College of Pharmacy of the University of Florida's Internet site, the email "had been a cause of concern for many people across the world".
A thorough search of various resources revealed no evidence of the existence of Progesterex. The United States Food and Drug Administration, the agency responsible for approving all human and animal medications, had no information on Progesterex in the "animal drugs" section of its website, and, said Joan Thompson, a pharmacist at the Florida College of Veterinary Medicine, there was no reference anywhere in the country in any of their literature on Progesterex or any veterinary medication that could be used to permanently sterilise horses.
But it doesn't really end there. Already, teenage girls are wary of the date rape drug syndrome.
Those seeing this scare email are likely to worry even more.
Claire Savage, a drug information officer for Sanca in Durban who works mostly with adolescents and pre-adolescents, said: "Whoever the sick person is behind this email is making the jobs of drug counsellors even more difficult.
"We try to be really honest with teenagers, and when a scare story comes out and is then disproved, they start to wonder what else is merely a scare story."
Date rape drug cases were real, she said, and a lot of cases were probably unreported because many of the teenagers tended to feel guilty.
"It's like the guilt trip society lays on rape victims. 'You were wearing a short skirt so what else did you expect?'
"Or, 'You were in a pub drinking so it serves you right'.
"But many of the girls to whom this has happened are legitimately in a pub - they're 18 and it's quite legal for them to be there, and very often they've only had one drink before the drug is slipped to them.
"The tremendous guilt they then carry around because they're too embarrassed or scared to tell anyone about it really angers me.
"They need to talk it through with someone. If they can't talk about it with someone they know, they might want to phone an organisation like ours or like Lifeline."
The biggest risk, she said, was to those girls who drank.
"People tend to drink far too fast and often they're not always quite sure what effect the drink itself will have on them.
"So they won't be aware of what signs to look out for and if the drink were spiked, they wouldn't know anyway."