The average U.S. woman spends between $150 and $300 per year on feminine products, according to USA Today (this translates to approximately 17,000 tampons in your lifetime, not to mention bottles of feminine cleansing products like sprays, douches, washes and wipes), which means you’re an important contributor to this $5.9 billion U.S. industry. Unfortunately, as the products add up, so do the dollars—and the toxic exposure.

Research suggests you should consider putting these products at the top of your buy-toxin-free list. According to the journal Environmental Health Perspectives, the vagina can absorb fluids at a higher rate than skin—and vaginal absorption of estrogenic chemicals can become up to 80 times more concentrated in the body than if the same dose is administered orally.

“Exposure to hormone-mimicking chemicals like phthalates or parabens in feminine care products is likely much higher than similar exposure to other cosmetics absorbed through skin on other parts of the body,” says Switalski.

So, what chemicals are used in feminine care? Because the government doesn’t require companies to disclose their ingredients (and there are few barriers in place to prevent toxins from entering products in the first place), it’s hard to know for sure. But Women’s Voices for the Earth did some digging and released its “Chem Fatale Report,” which found that tampons and pads may contain dioxins, fragrance chemicals and pesticide residues, among other troubling ingredients, while wipes, washes and lubricants often contain ingredients ranging from parabens and fragrance chemicals to artificial colorings.

Considering the lack of industry transparency, it wasn’t surprising that the research found many feminine care products contained an unpleasant cocktail of ingredients, some of which are known reproductive toxins, endocrine disruptors and allergens.

Check the ingredients on your feminine care products. Look for hazardous ingredients that may include methylchloroisothiazolinone, methylisothiazolinone, parabens, quaternium-15, DMDM hydantoin, iodopropynyl butylcarbamate, Triclosan and unknown fragrance chemicals.