Snake Oil: The Accuracy of Medical Information on the Internet
If you are reading this you probably know that the Internet -- particularly
the World-Wide Web -- is a widely-used source of medical information for the
lay public (patients and their families) as well as a great resource for
medical professionals. However, there's a problem: there is no guarantee
that the information you find on the Internet is accurate, much less useful.
There are many reasons for this.
- The Internet was designed as an anarchy.
- It was not intended for scheduling travel, meeting people, or selling fake
(and sometimes real) drugs via junk mail. It was designed to allow computer
A on a network of computers to send data to computer B -- even if half of
the intermediate computers were nuked. (Really. The Internet started as
a Cold War-era Defense Department project on reliable computer-to-computer
communications. For that matter, digital computers themselves originated
in part as a spinoff of the Manhattan Project.)
- The Internet has very loose central control.
- This was part of the redundant design, and became entrenched during the
original expansion of the Internet to academia and industry, long before
the general public had access.
- It is incredibly easy to connect new computers.
- Just about anyone can buy a computer, take it home, and have it connected
to the Internet within 30 minutes (or less) of getting home.
- 7-year-olds can set up Web sites.
- (And some of them do a better job than some of the professionals.)
- Sites come and go rapidly.
- (Some only last a few days...)
- Computers are cheap.
- You can buy a new Internet-capable computer for well under $1000
these days -- and a used Internet-capable computer for only a few hundred.
(And if you build them yourself -- as I do -- they're even cheaper.)
- Internet access is cheap.
- (As little as $9.95 a month. Some companies even give Internet access
away for free -- as long as you put up with the online ads. And public
libraries and schools have Internet-capable computers available to the
public for free.)
- Web pages are cheap
- (In fact, they can be free, either from your Internet service provider
or from companies who give away Web space in return for ads appearing on
- (Almost) everybody uses computers
- (Just look at E-mail,
Amazon.com, and eBay!)
- E-commerce was nonexistent in 1990
- (Again... look at
Amazon and eBay!)
- Many patients and families spend more time on the Net than talking
with their doctors
- (which explains a few things...)
The Dangers of Medical Misinformation
Can bad Web pages hurt someone?
Unfortunately, since the Internet is in essence an anarchy, there is no
guarantee -- and no way to guarantee -- that the information you find on the
Web is accurate. For some things, this isn't a problem: knitting instructions
are most likely to be used by people who can easily detect errors, and the
exact wording of the Monty Python Spam sketch is only of interest to us truly
obsessed purists. (For you purists out there: the Green Midget Cafe did not
serve lobster thermidor aux crevettes in a Provencale manner, with or
without Spam. If you have doubts, look at the original
Spam sketch on DVD.)
Medical information is another matter entirely -- bad information can
hurt someone. An example (from Crocco, Villasis-Keever, and Jadad,
Pediatrics (the journal of the
American Academy of Pediatrics), vol.109
(issue 3), pages 522-523, March, 2002):
A 1-year-old boy developed nausea and vomiting, followed by diarrhea. He was
seen at a local emergency room, diagnosed with an ear infection, and given
Two days later he still had diarrhea, and his parents took him back to the ER.
They were told that he had
gastroenteritis with dehydration, and were instructed to
(This is not the advice I usually give in this situation: my advice,
fluids, is rather different -- and much more in keeping with generally
accepted treatment for gastroenteritis and dehydration.)
- stop the antibiotics
- stop giving him solid foods, and
- rehydrate with soft drinks or fruit juice.
When the parents brought their child home, they looked on the Web for
information about diarrhea in children. They found a Web site with information
"from a purported tertiary care pediatric medical center in the US" (I'm
quoting the article here -- and, no, I do not know which medical
center it was.) The instructions from the "purported tertiary care ... center"
- Give clear fluids ("These may include Pedialyte, flat cola, ginger ale,
tea with sugar, Kool Aid, or Jello") every 2-3 hours.
- For children drinking regular milk: give no milk or milk products for 1
- "Call your doctor if your child does not urinate for over 12 hours."
Over the next 7 days, the parents followed this advice. The little boy
continued to have diarrhea and became increasingly weak.
On day 10 they took him to his regular doctor, who immediately put him in the
hospital. He was reportedly "pale, irritable, and appearing wasted" but,
fortunately, his electrolyte (sodium and potassium) levels were still in the
He was started on Pedialyte and restarted on solid foods, and was better
enough to go home in two days.
His parents, of course, were rather upset -- especially as they adamantly
maintained that they followed the ER and Web instructions carefully ... and
"could not understand why their child had not improved... as they had followed
the recommendations carefully." They were able to show their son's doctors a
printout of the Web page they had relied on, and the doctors found that,
indeed, "(they) had not misinterpreted the information on the site, which did
not conform to standards of care outlined in any available clinical practice
guideline (for the treatment of gastroenteritis)."
The parents gave permission for their child's case to be reported. The paper's
authors claim -- and I agree -- that this case may be the first published case
in which a patient was harmed because of bad advice posted on the Internet.
How much bad information is out there -- and how can you tell it's bad?
So, how does a Web surfer figure out what medical advice is good and
what advice is bad? Not easily, unfortunately. And there are a number of
studies showing that there is a lot of bad information out there. One
example was published by Pandolfini, Impicciatore, and Bonati
(Pediatrics, vol. 105 (issue
1), pages e1-e8, January, 2000). The authors were trying to see if "technical"
criteria which any reader could check, such as:
had any relationship to whether the information on the page was complete and/or
- whether the author identified him/herself on the Web page
- whether the author's qualifications (MD? RN? others? none?) were given on
- whether the page shows the date on which it was last revised
- whether the page states that it is not a substitute for your own doctor's
- whether there are links to other pages on the same subject, and
- whether the page lists references
It didn't. Even worse, not only was there no correlation between technical
completeness and completeness of information, or between technical completeness
and accuracy of information, but there was also no correlation between
completeness of information and accuracy of information. The subject they chose
was cough in children. They looked at how complete each page they reviewed was
as far as information on causes of cough, and at how accurate each page was on
how to treat cough (the gold standards for accuracy were the recommendations of
the AAP and the World Health Organization).
Of the 19 pages they looked at,
- only 4 pages met over half of the technical criteria.
- only 9 pages met over half of the completeness criteria.
- only 6 pages had more accurate than inaccurate information on treatment.
- only one page had more than 50% accurate information on treatment.
Only one of the 19 pages scored at the top in all three categories.
It happened to be my page
on coughs, colds, and runny noses. The only points the authors docked
me for were
- Only 2 of the 3 most technically-complete pages had complete information
on causes of cough.
- Only 1 of the 3 most technically-complete pages had more accurate than
inaccurate treatment information (of 6 treatment options the authors
considered one page had a 0 score, and one had a -4).
- Only 1 of the 3 pages with complete information on causes of cough
had more accurate than inaccurate treatment information (the
other two had -4 accuracy scores).
- that I did not include references or links to other resources (can you
blame me, after these results?), and
- that I did not mention multiple-ingredient cough-and-cold medicines (which
was also deliberate -- I don't think they work any more than
so I didn't waste the storage and bandwidth discussing them).
I might add that at the time the article was published in Pediatrics I
received several calls from the lay press asking me to comment on the findings.
I confess I was flattered by the attention. It is sad, though, that I would
attract national attention merely because I was the only Webmaster reviewed in
the paper who actually did everything right.
Unscientific and unsupported information
Another big -- and growing -- problem is the proliferation of Web sites devoted
to alternative therapies -- which isn't all bad: some alternative therapies
have been unjustly ignored by our profession. What is bad is the proliferation
of Web sites that advocate things that are known to be useless or even
harmful. Two examples:
- Web sites that oppose routine vaccination of children against common
- Antivaccination Web sites have been examined in the medical literature:
one report, by Wolfe, Sharp, and Lipsky, (published in the
Journal of the American Medical
Association, vol. 287 (issue 24), pages 3245-3248, June, 2002),
describes 22 Web sites examined by the authors. They found that:
- every one of the 22 sites claimed that vaccines, or their preservatives,
cause "idiopathic" illness. ("Idiopathic" is a term we use in the
medical profession to refer to diseases whose pathology (causes)
cannot yet be figured out by us idiots.) Among the disorders these
sites blame on vaccines and/or preservatives are:
Some of these problems might be vaccine-related. However, there
is no credible evidence that they are related to vaccine use. (Criteria
for scientific evidence does not seem to bother most of the people who
post material like this on the Web: they tend to pounce on any
information that supports their beliefs, while dismissing any evidence
that they are wrong as having been biased by vested interests such as
drug and vaccine manufacturers. I have wondered how they account for
all the companies that have left the vaccine business in the
last few years -- one reason we now have a shortage of some vaccines,
including the influenza
- immune dysfunction,
- neurologic disorders including seizures, brain damage, learning
disorders, ADD, and antisocial behaviour, and
- atopic disorders (asthma, eczema, and allergic rhinitis)
- 12 of the 22 sites claimed that supposedly contaminated lots of vaccine
are associated with an increased risk of adverse effects. Again, there
is no credible evidence that this is the case. Occasional "bad" lots
(due to possible bacterial contamination, or merely not as effective as
they are supposed to be) are occasionally identified, and are very
quickly pulled from the market, and so are vaccines that prove to have
bad side effects, such as the first
vaccine after we discovered that some babies develop bowel intussusception.
- 11 of the 22 claimed that there is an increased risk of adverse effects
with simultaneous administration of several vaccines at one office
visit. No one has shown this to be true in a well-designed study.
- 21 of the 22 claimed that vaccines (or their preservatives) erode
immunity and induce autoimmunity -- again, without credible evidence.
- 18 claimed that vaccine-induced immunity is temporary or ineffective.
That is true for some vaccines (such as
vaccine), but not in general -- most vaccines to childhood illnesses
give lifetime immunity to those diseases just as natural diseases do,
without having to have the illnesses.
- 21 sites claimed that adverse reactions are underreported.
- 16 sites claimed that we don't need to vaccinate against many diseases
because their incidence has declined -- without mentioning that the
incidence has declined precisely because we vaccinate all
susceptible children. (If these people are right about this, then why
aren't we still vaccinating against smallpox?)
- 15 sites promote homeopathy as an alternative to vaccination. There
have been studies showing that homeopathy may be useful for some
diseases, but none showing that homeopathy prevents infectious diseases.
- 20 sites claimed that vaccine policy is motivated by profit or other vested
interests. Many, if not most, of these sites dismiss studies showing
the safety and efficacy of vaccination -- if not because of study flaws,
then because the studies were funded by vaccine manufacturers or by
governments (who, as everyone knows, have hidden vested interests in
vaccine manufacture and usage).
- 17 sites claim that mandatory vaccination is a violation of civil
liberties. This might possibly be true, but I haven't heard many other
people question the right of the state to protect the majority of its
citizens from dangers posed by a minority -- including from crime or from
communicable diseases. Would these people object to the quarantine of
someone who had smallpox or anthrax?
- 7 of the sites claimed that vaccines are manufactured using aborted fetal
tissue. Most vaccines are made by growing the viruses in culture, usually
with animal tissue (such as eggs), or by recombinant DNA techniques, using
baking yeast to hold the recombined DNA and produce antigens. Three vaccines
hepatitis A, and
(German measles) are grown on cultured human tissue. The chickenpox
vaccine was originally grown in cultures of lung cells from human
embryos, but my understanding is that it is now grown using other human
tissue cell cultures; the rubella and hepatitis A vaccine viruses are
also produced with cultured tissue, and the cultures were originated from
tissue samples taken from volunteers. (I'm still looking into where the
tissue cultures come from, but they are not from wholesale harvest
of human embryos.)
- Web sites that promote unhealthy and illness-related behaviour
- I am experienced at treating medically-unstable patients with
eating disorders (anorexia and bulimia), and treat such patients
on a referral basis.
Treating two or more eating disorder patients at once has always been difficult,
because when we have two anorexics together they tend either to compete to see
how much more weight they can lose, or to start swapping tips on how to avoid
eating and how to continue losing weight. The Internet has made things
much worse: there are numerous Web sites run by anorexics or bulimics that
post advice on how to continue being anorexic or bulimic. In my opinion, that
is not much different than posting instructions on how to commit suicide. I
have never had one of my eating-disorder patients die, but I've certainly had
some come close and I really don't need to see one succeed -- and neither do
my patients, their families, or their friends.
How can we find good medical information on the Web?
It's not easy. An awful lot of Web-based medical information isn't worth the
time it takes to download. The problem is sorting out the wheat from the chaff.
And you can't depend on external forces to get rid of bad medical information.
Not only is regulating the Web legally difficult in most democratic countries
(it's certainly unconstitutional in the United States), but it's also technically
impossible. (Remember: the Internet was designed to transmit information reliably
even under nuclear attack.) Suing people who harm others by posting bad
information may get rid of some of the garbage, but it may also drive the good
medical Webmasters off the Web (there's a reason for that
disclaimer at the end of every one of my Web pages...) -- and, given the
international nature of the Internet, where would one file such a suit?
There are some things you can do to lessen the chances of running into bad
- Ask your doctor to suggest sites s/he thinks are well-written and
- Most of us are happy to recommend good sites -- whether or not we wrote
them ourselves (*smile*).
(Seriously, one reason why my Office on
the Web exists is so that my patients and parents would have a source
of information on common problems that I felt comfortable steering them to.
When I first set up this site there weren't that many resources on the Web;
now there are many more, but I still start parents out here because I know
-- and they know, too -- that what I say here is exactly what I would tell
them in person.)
- Browse the medical professional organizations' Web sites.
- Most of the professional-organization sites have sections written
specifically for patients and families. The
American Academy of Pediatrics Web site
is one good example. (And, yes, I am a Fellow of the AAP -- but I was
recommending their site long before I became a Fellow.) The information
on the professional-organization sites has been reviewed by members of the
organization for accuracy, and the sites are updated regularly. They also
check the accuracy of many or most of the sites to which they link.
- Browse public-health Web sites...
- Unless you actually are into conspiracy theories, public health authorities
will prove to have up-to-date information on many health-related issues.
CDC in particular is one of the best and
most current sources of information on infectious diseases -- both domestic
and for foreign travel. (My Web pages on
infections and immunizations are
based largely on information from the CDC and the
- Check each Web site you read for the author's name and qualifications and
the date when the page was last revised.
- Although this may not assure accuracy, it helps to know who wrote the page,
how old or new it is, and what qualifications the author has to say what's
The Health on the Net Foundation, based in
Switzerland, is dedicated to improving both the usability and the accuracy
of medical information on the Internet. They have developed a code of conduct,
HONCode, to which many medical Webmasters subscribe. The foundation
reviews Web sites to insure that the code of conduct is observed, and
Webmasters are not allowed to use the foundation's logo unless they meet
the code's requirements, which include
link here is to my site's listing at the foundation; I have subscribed to the
code for many years.)
- identifying the author of each page and stating his/her qualifications.
- showing the date of last revision
- stating that the page is not a substitute for professional care
- revealing the source of financing for the site, including any potential
conflicts of interest (like drug-company-financed sites)
- an explicitly-stated policy on privacy for site visitors, and
- providing an electronic means (which may be E-mail or a feedback form)
for a visitor to contact the Webmaster.
- Be careful out there!
- The Internet is a great place to find medical information -- but you
need to be careful about where you find that information. When you have
doubts, your doctor is the best person to ask for advice -- after all, your
doctor knows you a lot better than a Webmaster does.
Detailed Search page for complete instructions on searching the Office.
Search the Office for:
Back to Dr. Reddy's Pediatric Office on the Web
Sources We Use in the Office
We welcome your
comments and questions.
PLEASE NOTE: As with all of this Web site, I try to give
general answers to common questions my patients and their parents ask me
in my (real) office. If you have specific questions about your
child you must ask your child's regular doctor. No doctor can give
completely accurate advice about a particular child without knowing and
examining that child. I will be happy to try and answer
about children's health, but unless your child is a regular patient of
mine I cannot give you specific advice.
We comply with the Health On the Net
HONcode standard for trustworthy health information.
Click here or on the seal to verify.
Copyright © 2005, 2006, 2007
Vinay N. Reddy, M.D. All rights reserved.
Written 04/29/05; last revised 09/17/07