16 June, 2003 - Primate Toxity Trial of Intravaginal Lime Juice - Fully detailing earlier 2003 report

Professor Short reports:

If pre-coital intravaginal lime (or lemon) juice is to be advocated as a contraceptive, it is essential to establish whether repeated application of this acidic liquid to the vaginal mucosa produces any adverse effects on the vaginal or cervical epithelium.

Following advice from Melbourne's Royal Women's Hospital Clinical Ethics Advisory Group, we initiated a study on Cynomologous Monkeys (Macaca fascicularis) at the Primate Centre, Bogor Agricultural Institute, Indonesia, under the supervision of Dr Charanjit Bambra of Monash University, who was preset in Bogor during the time of the study in late December 2002 - January,2003.

Six treated monkeys were individually housed, and each was given a cotton wool ball soaked in about 0.8 ml fresh, undiluted lime juice daily from the first day of menstruation for 28 days. At the end of that time, the animals were killed and the complete reproductive tracts removed and fixed in 10% formal saline.

Six control monkeys, individually housed, had a vaginal biopsy taken on the first day of menstruation. This was then fixed in 10% formal saline.

The fixed specimens were then air freighted to Australia. The complete reproductive tracts, after removal of the ovaries and uterus, were bisected down the mid-line. Two of the 6 animals still had cotton wool balls in place. They were removed prior to embedding, sectioning, and staining with Haematoxylin and Eosin.

The stained sections of the six treated and six control animals were examined by Dr Mingjia Li and Prof. R.V.Short. In summary, the vaginal epithelium of the treated animals did not appear to differ in any way from that of the controls. The cervical epithelium of the treated animals also appeared normal. The only obvious abnormality was that most of the treated and control animals showed signs of chronic focal sub-mucosal infection, with aggregations of leucocytes. Since the overlying epithelium was entirely normal, it was concluded that these lesions were long-standing, and not related to the treatment. Such lesions are a common finding in wild-caught Macaques (Miller & Shattock, Microbes and Infection 5,59-67 (2003)).

In order to make absolutely sure that these lesions were not a result of the lime juice treatment, the sections were taken to Dr Miller at the University of California National Primate Research Center in Davis, California. He personally examined them, together with a pathologist colleague at the Center, and they agreed with our overall conclusion that there were no cervical or vaginal lesions in any of the treated animals that could be attributed to the lime juice administration. The sub-mucosal lesions, which they said were common in wild macaques, were possibly due to chronic simian papilloma virus infection.

In conclusion, repeated intravaginal administration of lime juice daily for a month caused no morphological abnormalities in the vagina or cervix of six treated monkeys. Since none of the animals were mated, there was no possibility that the acidity of the lime juice would be neutralized by the buffeting capacity of semen. Thus this trial was exposing animals to an extreme situation, with relatively large doses of acidic lime juice.

These reassuring negative findings give us every confidence in proposing a clinical trial of intravaginal lime juice in human volunteers to test its contraceptive efficacy.

Prof. R.V.Short
F.R.C.OG. F.A.A. F.R.S.