Every week or so, I get an e-mail from friends checking whether the latest 'pass this warning on to everyone' e-mail is genuine.
I'm always amazed by how many people trust and accept the information in them. A quick scan of the 'forwarded by' list shows these things pass through communities around the world faster than the influenza virus.
I've written about these medical warning chain e-mails before, but there are a couple of new ones that have been doing the rounds recently.
One appears to be the first home-grown health-scare internet chain and has gone around the world many times. It first surfaced in Hong Kong in 2003 and was so convincing that the Manila Times investigated the claims, which are that certain brands of lipstick (all named in the e-mail) have high lead content. Needless to say, the claims proved to be false.
It starts by claiming that one brand - which had only just entered the Hong Kong market when the chain e-mail began circulating - has reduced its lipstick price more than six-fold because it knew it contained lead.
It then says lead gives you cancer, something that again should raise suspicions because it doesn't say which cancer, how the lead in lipstick does this or what science there is to support it.
You might think this is because it's simply helpful advice from someone who's not a professional or a scientist. But this should make you ask whether you can trust information from someone who doesn't understand the science the claims are based on.
Many of these e-mails claim the information comes from medical journals, newspapers or medical websites. Often, when you check the source, the journal, newspaper or website doesn't exist (but has a name similar to a real one), or if it does, has never published the claims.
Another thing that should make you suspicious is an e-mail containing a specific, shocking claim that names names.
Such information, if true, makes it into the news media long before it gets onto the internet, so you have to ask why the first you've heard of it is in a chain e-mail. And this one sounds like blatant industrial sabotage.
The other recent bit of internet advice is a list of 'don'ts', complete with pictures, that the anonymous author insists medical science has found to be dangerous after eating.
The first I have to support. It says: don't smoke. Unfortunately, it applies very strange logic, claiming your chances of getting cancer are higher if you smoke after meals. They're not. You get cancer from smoking, whether it's first thing in the morning, the middle of the night or in the bath.
The more you smoke, the higher your chances of getting cancer, as well as your chances of heart disease, premature ageing, impotence, high blood pressure, a stroke ... you name it, smoking delivers.
Other things mentioned - such as don't loosen your belt, don't rest after eating - are just silly.