The immobilization of all spermatozoa in vitro by bitter lemon drink and the effect of alkaline pH.

Unlabelled: 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. Semen was collected from 7 men, average age 28 years, of proven fertility, after 5 days' abstinence from sexual intercourse. The temperature and pH of the drinks were adjusted from 22 degrees C (room) to 37 degrees C, and pH 2.4 (acid) to 7.5 (alkaline), respectively. The mean % motility of spermatozoa in the adjusted and in the unadjusted drinks was compared for significant differences at the 1% level using the student's t-test. The results showed no significant differences in mean % motility in the drinks at 22 degrees C and at 37 degrees C. The mean % motility in all the drinks, except Coca-Cola, was significantly greater at alkaline than at acid pH; for Coca-Cola, motility was significantly greater at acid than alkaline pH. 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.