A simple, low-cost screening method is showing remarkable promise in the fight against cervical cancer in developing countries — a discovery that has implications for millions of women in places where conventional Pap smear infrastructure does not exist.

The method, called visual inspection with acetic acid, involves applying ordinary household vinegar — diluted acetic acid — to the cervix and examining the results with the naked eye. Precancerous cells turn white under the vinegar, making them visible to a trained health worker without any laboratory equipment. If abnormal cells are found, a freezing treatment called cryotherapy can destroy them immediately in the same visit.

Cervical cancer kills approximately 275,000 women annually worldwide, with roughly 85 percent of those deaths occurring in developing countries where the disease is often diagnosed only at advanced stages because screening programs don't exist. The vinegar screening method, which costs roughly as little as three dollars per test including treatment, could change that calculus dramatically.

Clinical trials conducted in India and other countries have found that the vinegar method, despite its simplicity, catches a significant proportion of the precancerous lesions that more sophisticated screening would identify. The same-day treatment capability is crucial: programs that diagnose abnormalities and then ask patients to return for treatment lose a large proportion of women to follow-up in resource-limited settings.

The Gates Foundation and other global health funders have invested in scaling the approach across sub-Saharan Africa and South and Southeast Asia. The result, researchers project, could save tens of thousands of lives annually at a fraction of the cost of conventional cervical cancer control programs.