One of the reasons why Coca-cola is not an effective spermicide is because sperm are faster and may reach an egg in time to fertilise it, says an expert in the Christmas issue published on bmj.com.
The author, Deborah Anderson, a professor in obstetrics and gynaecology at Boston University and Harvard Medical School, writes that Coca-cola douches were allegedly used during the 1950s and 60s as a contraceptive when other methods were not easily available. The acidity alledgedly worked as spermicide to kill sperm and the classic coke bottle shape lent itself to a "shake and shoot" applicator!
In this analysis, Professor Anderson provides eight reasons why you're better off not reaching for a Coca-cola after sex, unless you want to drink it:
Coca-cola is not very effective in killing sperm.
Sperm are faster than Coca-cola and could escape douching and reach the cervical canal.
Coca-cola may be good for tenderising steaks and removing corrosion from car bumpers but is not good news for vaginal tissue. Coca-cola damages the top layers of cells and could make a woman more prone to sexually transmitted infections.
The good bacteria that keep vaginas healthy could be adversely affected by coke and this could result in fungal and bacterial infections.
Douching could lead to pelvic inflammatory disease and ectopic pregnancy.
The Coca-cola formula is a secret so this means no research has been done on whether it would cause birth defects.
You need skill to douche effectively with Coca-cola - not practical, especially in the dark when bottle caps can go dangerously astray.
There are much more effective and easy to use methods of contraception around.