This one sorta long but really got people believe in it one
Claim: Coca-Cola is an effective spermicide.
Status: False.
Origins: Somehow I doubt this is what Coca-Cola meant by 'the pause
that refreshes.'
Here's a short newspaper summary from 1985 about the first study
undertaken to verify claims about Coke's contraceptive
properties:
'OLD COKE' BETTER THAN 'NEW COKE?'
Common commodities such as honey and sodium bicarbonate, acidic
fruit juices and oils have been used through history as
spermicides. Three Harvard researchers note that Coca-Cola is said
to be favored for this purpose in some developing countries and
was
touted in American folklore as a contraceptive aid in years gone
by. No documentation of the soft drink's spermicidal capabilities
was found, so Dr. Sharee Umpierre and two colleagues decided to
test Coke in some of its various formulations in their lab. They
found that Diet Coke was a most effective spermicide and the
original formula Coke was also quite effective, five times more so
than the reformulated "new" Coke. "Although not recommended for
postcoital contraception, partly because sperm can be found in the
oviducts within minutes after intercourse, Coca-Cola products do
appear to have a spermicidal effect," the researchers said in a
letter to the New England Journal of Medicine. "Furthermore, our
data indicate that at least in the area of spermicidal effect,
'Classic' Coke is it."
[T]he researchers said they found marked differences in the ability
of four different Coca-Cola formulations to act as a spermicide. At
the same time, they warned against the use of soft drinks of any
kind as douches after intercourse to prevent pregnancy. While there
are differences among soft drinks, all fail as effective
contraceptives, the researchers noted.
To test the sperm-killing abilities of various Coca-Cola products,
the three researchers prepared test tubes containing small samples
of carefully preserved sperm and poured in small amounts of Diet
Coke, New Coke, caffeine-free New Coke and Classic Coke carefully
repeating the test three times for each soda.
All of them killed some sperm, but New Coke turned out to be least
effective, with Diet Coke having the most pronounced effect overall
and Classic Coke recording a five times greater sperm-killing rate
than its upstart rival. "Coca-Cola products do appear to have a
spermicidal effect," the study deadpanned. "Furthermore, our data
indicate that, at least in the area of spermicidal effect, 'Classic
Coke' is it."
Coca-Cola saw little humor in the Harvard project. A spokesman said
the company hadn't seen the new report, but "our position is we do
not promote any of our products for any medical use."1
However, other researchers were unable to verify these results in
later experiments. Subsequent trials performed by medical
researchers in Taiwan (using several varities of both Coca-Cola and
Pepsi-Cola) led them to the opposite conclusion, that "cola has
little if any spermicidal effect":
The inhibitory effect of Old Coke, caffeine-free New Coke, New
Coke, Diet Coke and Pepsi-Cola on human sperm motility was studied
with a trans-membrane migration method. None of them could decrease
sperm motility to less than 70% of control within one hour. A
previous study which claimed a marked variation of spermicidal
potencies among different formulations of Coca-Cola could not be
confirmed. Even if cola has a spermicidal effect, its potency is
relatively weak as compared with other well-known spermicidal
agents.
Testing of various cola formulas on sperm motility using a
trans-membrane procedure did not decrease motility to less than 70%
control in a 1-hour period. Diet Coca-Cola had the strongest
spermicidal effect followed by Classic Coca-Cola, Caffeine-free
Coca-Cola and New Coca-Cola. Since there are no known substances in
cola that effect cellular membranes, the results of these tests
were not unusual. Other tests have been done using higher dilution
of cola which could effect sperm motility and give different
results for spermicidal potencies. The results show that cola has
little if any spermicidal effect. Its use in postcoital douching is
ineffective and could cause complications such as infection.2
Whichever set of results one wants to believe, those tempted to
grab a six-pack and head down to the beach should keep in mind that
spermicides themselves aren't all that effective at preventing
pregnancy. Saying Diet Coke kills sperm is like saying a rubber
glove makes a decent balloon you shouldn't interpret either as
meaning that using them creatively will keep you safe from
parenthesis. (That's when you wind up pregnant and end up writing a
book about it.)
Coca-Cola may not be promoting its product as a spermicidal douche,
but the idea ain't new. Coke (and Dr. Pepper in the southern
States) douches have been part of contraceptive lore at least since
the 1950s, with the common belief being that the carbonic acid in
Coke killed the sperm and the sugar "exploded" the sperm cells,
while the carbonation of the drink forced the jet of liquid into
the vagina. Back in the 1950s and 1960s, this method of parenthood
prevention proved somewhat popular because not only was it cheap
and universally available at a time when reliable birth control
methods were hard to come by, but it also came in its own handy
"shake and shoot" disposable applicator. After intercourse, the
girl would uncap a warm Coke, put her thumb over the mouth of the
bottle, shake up the beverage, then insert the neck of the bottle
in her vagina and move her thumb out of the way. The warm
well-shaken Coke became an effervescent spermicidal douche, with
the traditional (at that time) six-ounce bottle providing what was
deemed to be just the right amount for one application.
As stated above, this method wasn't all that effective at
preventing pregnancy. Though Coca-Cola might have been a (slight)
step up from plain water, douching with any liquid is far too often
a case of attempting to close the barn door after the horse has got
loose. By the time the douche is fired off, 100,000 or thereabouts
sperm are swimming around in the uterus, already out of reach of
any douche, even a fizzy one. Women should be reluctant to turn to
soda pop douches for another reason besides their ineffectiveness
at preventing Momhood the sugars in them being let loose in that
part of a woman's anatomy can lead to yeast infections, an
annoying, difficult-to-cure condition.
Oddly, a 1992 study conducted by Nigerian researchers found that,
although Coca-Cola and Pepsi-Cola were ineffective as spermicides,
Krest bitter lemon drink fared quite well in this regard, and they
recommended additional study to determine whether it might have
"great potential as such a contraceptive":
This study investigated the effects of increase in temperature and
in pH of Coca-Cola, Afri-Cola, Pepsi-Cola and Krest bitter lemon
drinks ("soft drinks") produced in Nigeria on the in vitro motility
of spermatozoa. Of the drinks, Krest bitter lemon (unadjusted)
immobilized all spermatozoa within 1 minute of addition.
Conclusion: i) alkalinity decreases the spermicidal action of all
drinks except Coca-Cola, and ii) Krest bitter lemon may achieve
very high efficacy if used as post-coital douche, especially in the
impoverished, densely populated Third World.
Other than Krest bitter lemon, the significant decreases in sperm
motility were not enough to prevent pregnancy. These findings
indicated that researchers should test Krest bitter lemon for
effectiveness as a postcoital contraceptive. If indeed it proves
effective, it has great potential as such a contraceptive among the
poor in the densely population developed countries since it is
readily available and inexpensive.3
The bottom line? The best contraceptive use for a Coke is to use it
wash down your daily birth control pills with.
